Patent Publication Number: US-11656676-B2

Title: System, apparatus and method for dynamic thermal distribution of a system on chip

Description:
TECHNICAL FIELD 
     Embodiments relate to powering a processor with internal voltage regulators. 
     BACKGROUND 
     In modern processors, power can be supplied from an external power supply such as one or more voltage regulators. Internally to a processor, oftentimes there are one or more integrated voltage regulators to further regulate an incoming voltage and provide it to processing units within the processor. Integrated voltage regulators offer overall system power reduction opportunities by operating a transistor at a lower voltage than is possible with an external voltage regulator due to faster response time and elimination of board/package impedance and inductance. The active power savings at the transistor is a squared of the voltage reduction. However, the voltage reduction is done at a cost of regulator efficiency. 
     Using an internal regulator and reducing power can translate to performance improvement opportunities. However, concentration of on-die regulators in one place on the die as typically implemented due to inductance locality issues can create localized hot spots. This arrangement can exacerbate hot spots, and in some cases limit the potential gains in performance that integrated regulators promise. In worse case scenarios, peak performance can actually suffer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram of a portion of a system in accordance with an embodiment of the present invention. 
         FIG.  2    is a block diagram of a processor in accordance with an embodiment of the present invention. 
         FIG.  3    is a block diagram of a multi-domain processor in accordance with another embodiment of the present invention. 
         FIG.  4    is an embodiment of a processor including multiple cores. 
         FIG.  5    is a block diagram of a micro-architecture of a processor core in accordance with one embodiment of the present invention. 
         FIG.  6    is a block diagram of a micro-architecture of a processor core in accordance with another embodiment. 
         FIG.  7    is a block diagram of a micro-architecture of a processor core in accordance with yet another embodiment. 
         FIG.  8    is a block diagram of a micro-architecture of a processor core in accordance with a still further embodiment. 
         FIG.  9    is a block diagram of a processor in accordance with another embodiment of the present invention. 
         FIG.  10    is a block diagram of a representative SoC in accordance with an embodiment of the present invention. 
         FIG.  11    is a block diagram of another example SoC in accordance with an embodiment of the present invention. 
         FIG.  12    is a block diagram of an example system with which embodiments can be used. 
         FIG.  13    is a block diagram of another example system with which embodiments may be used. 
         FIG.  14    is a block diagram of a representative computer system. 
         FIG.  15    is a block diagram of a system in accordance with an embodiment of the present invention. 
         FIG.  16    is a block diagram illustrating an IP core development system used to manufacture an integrated circuit to perform operations according to an embodiment. 
         FIG.  17    is a block diagram of a high level view of a processor in accordance with an embodiment. 
         FIG.  18    is a block diagram of a core in accordance with an embodiment. 
         FIG.  19    is a schematic diagram of a LDO in accordance with an embodiment of the present invention. 
         FIG.  20    is a cross-sectional view of a processor in accordance with an embodiment. 
         FIG.  21    is a flow diagram of a method in accordance with an embodiment of the present invention. 
         FIG.  22    is a flow diagram of a method in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In various embodiments, a processor or other system on chip (SoC) may be provided with integrated voltage regulators (IVRs) that are controllable, either dynamically or statically, to be enabled or disabled. More specifically, embodiments provide techniques to enable distributed IVR components to be enabled or disabled based on a priori information as to potential hot spots within the processor in cases of a static-based control. Instead, for dynamic-based control actual hot spot information identified during use may be used to dynamically control one or more IVRs or portions thereof to be enabled or disabled. 
     In some cases, techniques herein may be used to provide power to a given core or other processing unit from a locally located IVR when no thermal condition exists. Instead in the instance of a thermal condition, power can be provided from a more remotely located IVR. In embodiments the IVRs may take the form of low dropout regulators (hereinafter LDOs). In some cases, dynamic control may be used to control a number of power gates of a given LDO to enable to meet power requirements, while at the same time reducing heat dissipation around the location of one or more hot spots. In contrast, many typical IVRs are formed of a switching-type voltage regulator that implements inductors to provide for energy storage. In these typical IVRs, placement issues are exacerbated, as the IVRs are closely coupled with such inductors, which restrict their placement during physical layout. Also with typical IVRs, they are often located in a central location on a die, which can potentially create or exacerbate hot spots. 
     In contrast, with LDOs as described herein, layout constraints are eased, as the LDOs may be located virtually anywhere on a semiconductor die and may be associated with physically distributed power gates. With an oversubscription of distributed power stages, one or more regulators can be either fused off or dynamically turned off when located close to a hot spot. With embodiments, the thermal hot spots can see the thermal improvement from running at a reduced voltage with minimal impact from the IVR, increasing peak performance as compared to an evenly distributed power distribution solution, and even more significantly as compared to an implementation where the IVRs are concentrated in one location. Note that while embodiments herein address thermal control based on oversubscription and/or selective control of regulators and/or power gates, it is possible also to prioritize enabling of regulators and/or power gates so that these components most closely located near a thermal hot spot may be the last to be enabled and the first to be disabled, in fine grain control situations. 
     With oversubscription and disabling a portion of regulators, embodiments may resolve concerns with baseline placement of regulators, as many hot spots are scenario dependent (a case for dynamically controlling). In other cases, post-silicon correlation can be used to target the best places to reduce LDO activity (a case for fused disabling). In cases where a constant hot spot is known to exist prior to manufacture, reducing or eliminating one or more LDOs around that area can be accomplished at physical layout. For example, assume that a particular processor type (e.g., a graphics processor) is known to run at high temperatures. In this example, during layout LDOs may be located at more distant regions to the graphics processor in the processor design, or in less extreme cases, some lesser amount of LDOs may be located in close relation to the graphics processor. 
     In embodiments, LDO output stages may be statically fused to be off or dynamically turned off when associated with a localized hot spot. In one embodiment, such control may be at a high level and at a high granularity in which a processor is segmented into quadrants, where each quadrant may be controlled to operate at a percentage of discrete power gates. In this high level example, depending upon dynamic operating conditions (e.g., activity and/or temperature), 0%, 25%, 50% or 100% (as examples) of the power gates of an output stage of an LDO may be enabled for operation. As such with embodiments, peak performance may be increased in cases where a junction temperature (T j ) limits performance. Further for given use cases, embodiments may enable reduced power consumption by way of reducing hot spots. In various embodiments, hot spots may be minimized, as they may be evenly distributed throughout a die by way of the static, dynamic or combination of static and dynamic control of integrated voltage regulators as described herein. 
     Understand that embodiments provide for a wide variety of techniques and implementations that can be applied on different levels of granularity. In some cases, a processor die may include multiple LDOs that can be controlled on a region basis, e.g., on a quadrant basis. In other cases, greater or lower granularities are possible. For example, in some cases a processor can be segmented into 8, 16 or another number of segments, each having associated LDOs that can be individually controlled. Such individual control includes both enabling or disabling of a given LDO, as well as selective control of a number of power gates of the LDO to enable or disable. Understand that the control mechanisms also may be applied at different granularities. In some cases, a processor-wide power controller (such as a power control unit (PCU)) may be the primary agent responsible for the location-selective voltage regulator control described herein, e.g., based at least in part on thermal information obtained from sensors located throughout a processor. In other cases, the PCU may act in concert with additional power management agents, such as individual core-included power management agents that may control location-selective voltage regulator operations on a per core (or even smaller granularity) basis. 
     Although the following embodiments are described with reference to energy conservation and energy efficiency in specific integrated circuits, such as in computing platforms or processors, other embodiments are applicable to other types of integrated circuits and logic devices. Similar techniques and teachings of embodiments described herein may be applied to other types of circuits or semiconductor devices that may also benefit from better energy efficiency and energy conservation. For example, the disclosed embodiments are not limited to any particular type of computer systems. That is, disclosed embodiments can be used in many different system types, ranging from server computers (e.g., tower, rack, blade, micro-server and so forth), communications systems, storage systems, desktop computers of any configuration, laptop, notebook, and tablet computers (including 2:1 tablets, phablets and so forth), and may be also used in other devices, such as handheld devices, systems on chip (SoCs), and embedded applications. Some examples of handheld devices include cellular phones such as smartphones, Internet protocol devices, digital cameras, personal digital assistants (PDAs), and handheld PCs. Embedded applications may typically include a microcontroller, a digital signal processor (DSP), network computers (NetPC), set-top boxes, network hubs, wide area network (WAN) switches, wearable devices, or any other system that can perform the functions and operations taught below. More so, embodiments may be implemented in mobile terminals having standard voice functionality such as mobile phones, smartphones and phablets, and/or in non-mobile terminals without a standard wireless voice function communication capability, such as many wearables, tablets, notebooks, desktops, micro-servers, servers and so forth. Moreover, the apparatuses, methods, and systems described herein are not limited to physical computing devices, but may also relate to software optimizations for energy conservation and efficiency. As will become readily apparent in the description below, the embodiments of methods, apparatuses, and systems described herein (whether in reference to hardware, firmware, software, or a combination thereof) are vital to a ‘green technology’ future, such as for power conservation and energy efficiency in products that encompass a large portion of the US economy. 
     Referring now to  FIG.  1   , shown is a block diagram of a portion of a system in accordance with an embodiment of the present invention. As shown in  FIG.  1   , system  100  may include various components, including a processor  110  which as shown is a multicore processor. Processor  110  may be coupled to a power supply  150  via an external voltage regulator  160 , which may perform a first voltage conversion to provide a primary regulated voltage to processor  110 . 
     As seen, processor  110  may be a single die processor including multiple cores  120   a - 120   n . In addition, each core may be associated with at least one and potentially multiple integrated voltage regulators (IVR)  125   a - 125   x , each of which receives the primary regulated voltage and generates an operating voltage to be provided to one or more agents of the processor associated with the IVR. Accordingly, an IVR implementation may be provided to allow for fine-grained control of voltage and thus power and performance of each individual core. As such, each core can operate at an independent voltage and frequency, enabling great flexibility and affording wide opportunities for balancing power consumption with performance. As described herein, a controllable amount of IVRs  125  (which in an embodiment may be implemented as low dropout regulators (LDOs)) (and/or power gates thereof) may be enabled, based at least in part on thermal information such that dynamic thermal distribution within processor  110  may occur, as described more fully herein. 
     Still referring to  FIG.  1   , additional components may be present within the processor including an input/output interface  132 , another interface  134 , and an integrated memory controller  136 . As seen, each of these components may be powered by one or more other integrated voltage regulators  125   y . In one embodiment, interface  132  may be enable operation for an Intel® Quick Path Interconnect (QPI) interconnect, which provides for point-to-point (PtP) links in a cache coherent protocol that includes multiple layers including a physical layer, a link layer and a protocol layer. In turn, interface  134  may communicate via a Peripheral Component Interconnect Express (PCIe™) protocol. 
     Also shown is a power control unit (PCU)  138 , which may include hardware, software and/or firmware to perform power management operations with regard to processor  110 . As seen, PCU  138  provides control information to external voltage regulator  160  via a digital interface to cause the voltage regulator to generate the appropriate regulated voltage. PCU  138  also provides control information to IVRs  125  via another digital interface to control the operating voltage generated (or to cause a corresponding IVR to be disabled in a low power mode). In various embodiments, PCU  138  may include a variety of power management logic units to perform hardware-based power management. Such power management may be wholly processor controlled (e.g., by various processor hardware, and which may be triggered by workload and/or power, thermal or other processor constraints) and/or the power management may be performed responsive to external sources (such as a platform or management power management source or system software). 
     Furthermore, while  FIG.  1    shows an implementation in which PCU  138  is a separate processing engine (which may be implemented as a microcontroller), understand that in some cases in addition to or instead of a dedicated power controller, each core may include or be associated with a power control agent to more autonomously control power consumption independently. In some cases a hierarchical power management architecture may be provided, with PCU  138  in communication with corresponding power management agents associated with each of cores  120 . 
     One power management logic unit included in PCU  138  may be a location selective regulator controller, which may be used to control independent enabling and disabling of IVRs  125 , either completely or selectively controlling a number of power gates of a given regulator to enable or disable. 
     While not shown for ease of illustration, understand that additional components may be present within processor  110  such as additional control circuitry, and other components such as internal memories, e.g., one or more levels of a cache memory hierarchy and so forth. Furthermore, while shown in the implementation of  FIG.  1    with an integrated voltage regulator, embodiments are not so limited. 
     Note that the power management techniques described herein may be independent of and complementary to an operating system (OS)-based power management (OSPM) mechanism. According to one example OSPM technique, a processor can operate at various performance states or levels, so-called P-states, namely from P0 to PN. In general, the P1 performance state may correspond to the highest guaranteed performance state that can be requested by an OS. Embodiments described herein may enable dynamic changes to the guaranteed frequency of the P1 performance state, based on a variety of inputs and processor operating parameters. In addition to this P1 state, the OS can further request a higher performance state, namely a P0 state. This P0 state may thus be an opportunistic or turbo mode state in which, when power and/or thermal budget is available, processor hardware can configure the processor or at least portions thereof to operate at a higher than guaranteed frequency. In many implementations a processor can include multiple so-called bin frequencies above the P1 guaranteed maximum frequency, exceeding to a maximum peak frequency of the particular processor, as fused or otherwise written into the processor during manufacture. In addition, according to one OSPM mechanism, a processor can operate at various power states or levels. With regard to power states, an OSPM mechanism may specify different power consumption states, generally referred to as C-states, C0, C1 to Cn states. When a core is active, it runs at a C0 state, and when the core is idle it may be placed in a core low power state, also called a core non-zero C-state (e.g., C1-C6 states), with each C-state being at a lower power consumption level (such that C6 is a deeper low power state than C1, and so forth). 
     Understand that many different types of power management techniques may be used individually or in combination in different embodiments. As representative examples, a power controller may control the processor to be power managed by some form of dynamic voltage frequency scaling (DVFS) in which an operating voltage and/or operating frequency of one or more cores or other processor logic may be dynamically controlled to reduce power consumption in certain situations. In an example, DVFS may be performed using Enhanced Intel SpeedStep™ technology available from Intel Corporation, Santa Clara, Calif., to provide optimal performance at a lowest power consumption level. In another example, DVFS may be performed using Intel TurboBoost™ technology to enable one or more cores or other compute engines to operate at a higher than guaranteed operating frequency based on conditions (e.g., workload and availability). 
     Another power management technique that may be used in certain examples is dynamic swapping of workloads between different compute engines. For example, the processor may include asymmetric cores or other processing engines that operate at different power consumption levels, such that in a power constrained situation, one or more workloads can be dynamically switched to execute on a lower power core or other compute engine. Another exemplary power management technique is hardware duty cycling (HDC), which may cause cores and/or other compute engines to be periodically enabled and disabled according to a duty cycle, such that one or more cores may be made inactive during an inactive period of the duty cycle and made active during an active period of the duty cycle. Although described with these particular examples, understand that many other power management techniques may be used in particular embodiments. 
     Embodiments can be implemented in processors for various markets including server processors, desktop processors, mobile processors and so forth. Referring now to  FIG.  2   , shown is a block diagram of a processor in accordance with an embodiment of the present invention. As shown in  FIG.  2   , processor  200  may be a multicore processor including a plurality of cores  210   a - 210   n . In one embodiment, each such core may be of an independent power domain and can be configured to enter and exit active states and/or maximum performance states based on workload. The various cores may be coupled via an interconnect  215  to a system agent  220  that includes various components. As seen, system agent  220  may include a shared cache  230  which may be a last level cache. In addition, the system agent may include an integrated memory controller  240  to communicate with a system memory (not shown in  FIG.  2   ), e.g., via a memory bus. System agent  220  also includes various interfaces  250  and a power control unit  255 , which may include logic to perform the power management techniques described herein. In the embodiment shown, power control unit  255  includes a location selective regulator controller  258  that may, statically or dynamically, control powering of cores  210  and other components of processor  200  in a location selective manner, as described herein. 
     In addition, by interfaces  250   a - 250   n , connection can be made to various off-chip components such as peripheral devices, mass storage and so forth. While shown with this particular implementation in the embodiment of  FIG.  2   , the scope of the present invention is not limited in this regard. 
     Referring now to  FIG.  3   , shown is a block diagram of a multi-domain processor in accordance with another embodiment of the present invention. As shown in the embodiment of  FIG.  3   , processor  300  includes multiple domains. Specifically, a core domain  310  can include a plurality of cores  310   0 - 310   n , a graphics domain  320  can include one or more graphics engines, and a system agent domain  350  may further be present. In some embodiments, system agent domain  350  may execute at an independent frequency than the core domain and may remain powered on at all times to handle power control events and power management such that domains  310  and  320  can be controlled to dynamically enter into and exit high power and low power states. Each of domains  310  and  320  may operate at different voltage and/or power. Note that while only shown with three domains, understand the scope of the present invention is not limited in this regard and additional domains can be present in other embodiments. For example, multiple core domains may be present each including at least one core. 
     In general, each core  310  may further include low level caches in addition to various execution units and additional processing elements. In turn, the various cores may be coupled to each other and to a shared cache memory formed of a plurality of units of a last level cache (LLC)  340   0 - 340   n . In various embodiments, LLC  340  may be shared amongst the cores and the graphics engine, as well as various media processing circuitry. As seen, a ring interconnect  330  thus couples the cores together, and provides interconnection between the cores, graphics domain  320  and system agent circuitry  350 . In one embodiment, interconnect  330  can be part of the core domain. However in other embodiments the ring interconnect can be of its own domain. 
     As further seen, system agent domain  350  may include display controller  352  which may provide control of and an interface to an associated display. As further seen, system agent domain  350  may include a power control unit  355  which can include logic to perform the power management techniques described herein. In the embodiment shown, power control unit  355  includes a location selective regulator controller  359  that may, statically or dynamically, control powering of cores  310  and other components of processor  300  in a location selective manner, as described herein. 
     As further seen in  FIG.  3   , processor  300  can further include an integrated memory controller (IMC)  370  that can provide for an interface to a system memory, such as a dynamic random access memory (DRAM). Multiple interfaces  380   0 - 380   n  may be present to enable interconnection between the processor and other circuitry. For example, in one embodiment at least one direct media interface (DMI) interface may be provided as well as one or more PCIe™ interfaces. Still further, to provide for communications between other agents such as additional processors or other circuitry, one or more QPI interfaces may also be provided. Although shown at this high level in the embodiment of  FIG.  3   , understand the scope of the present invention is not limited in this regard. 
     Referring to  FIG.  4   , an embodiment of a processor including multiple cores is illustrated. Processor  400  includes any processor or processing device, such as a microprocessor, an embedded processor, a digital signal processor (DSP), a network processor, a handheld processor, an application processor, a co-processor, a system on a chip (SoC), or other device to execute code. Processor  400 , in one embodiment, includes at least two cores—cores  401  and  402 , which may include asymmetric cores or symmetric cores (the illustrated embodiment). However, processor  400  may include any number of processing elements that may be symmetric or asymmetric. 
     In one embodiment, a processing element refers to hardware or logic to support a software thread. Examples of hardware processing elements include: a thread unit, a thread slot, a thread, a process unit, a context, a context unit, a logical processor, a hardware thread, a core, and/or any other element, which is capable of holding a state for a processor, such as an execution state or architectural state. In other words, a processing element, in one embodiment, refers to any hardware capable of being independently associated with code, such as a software thread, operating system, application, or other code. A physical processor typically refers to an integrated circuit, which potentially includes any number of other processing elements, such as cores or hardware threads. 
     A core often refers to logic located on an integrated circuit capable of maintaining an independent architectural state, wherein each independently maintained architectural state is associated with at least some dedicated execution resources. In contrast to cores, a hardware thread typically refers to any logic located on an integrated circuit capable of maintaining an independent architectural state, wherein the independently maintained architectural states share access to execution resources. As can be seen, when certain resources are shared and others are dedicated to an architectural state, the line between the nomenclature of a hardware thread and core overlaps. Yet often, a core and a hardware thread are viewed by an operating system as individual logical processors, where the operating system is able to individually schedule operations on each logical processor. 
     Physical processor  400 , as illustrated in  FIG.  4   , includes two cores, cores  401  and  402 . Here, cores  401  and  402  are considered symmetric cores, i.e., cores with the same configurations, functional units, and/or logic. In another embodiment, core  401  includes an out-of-order processor core, while core  402  includes an in-order processor core. However, cores  401  and  402  may be individually selected from any type of core, such as a native core, a software managed core, a core adapted to execute a native instruction set architecture (ISA), a core adapted to execute a translated ISA, a co-designed core, or other known core. Yet to further the discussion, the functional units illustrated in core  401  are described in further detail below, as the units in core  402  operate in a similar manner. 
     As depicted, core  401  includes two hardware threads  401   a  and  401   b , which may also be referred to as hardware thread slots  401   a  and  401   b . Therefore, software entities, such as an operating system, in one embodiment potentially view processor  400  as four separate processors, i.e., four logical processors or processing elements capable of executing four software threads concurrently. As alluded to above, a first thread is associated with architecture state registers  401   a , a second thread is associated with architecture state registers  401   b , a third thread may be associated with architecture state registers  402   a , and a fourth thread may be associated with architecture state registers  402   b . Here, each of the architecture state registers ( 401   a ,  401   b ,  402   a , and  402   b ) may be referred to as processing elements, thread slots, or thread units, as described above. As illustrated, architecture state registers  401   a  are replicated in architecture state registers  401   b , so individual architecture states/contexts are capable of being stored for logical processor  401   a  and logical processor  401   b . In core  401 , other smaller resources, such as instruction pointers and renaming logic in allocator and renamer block  430  may also be replicated for threads  401   a  and  401   b . Some resources, such as re-order buffers in reorder/retirement unit  435 , I-LTB  420 , load/store buffers, and queues may be shared through partitioning. Other resources, such as general purpose internal registers, page-table base register(s), lower-level data-cache and data-TLB  450 , execution unit(s)  440 , and portions of out-of-order unit  435  are potentially fully shared. 
     Processor  400  often includes other resources, which may be fully shared, shared through partitioning, or dedicated by/to processing elements. In  FIG.  4   , an embodiment of a purely exemplary processor with illustrative logical units/resources of a processor is illustrated. Note that a processor may include, or omit, any of these functional units, as well as include any other known functional units, logic, or firmware not depicted. As illustrated, core  401  includes a simplified, representative out-of-order (OOO) processor core. But an in-order processor may be utilized in different embodiments. The OOO core includes a branch target buffer  420  to predict branches to be executed/taken and an instruction-translation buffer (I-TLB)  420  to store address translation entries for instructions. 
     Core  401  further includes decode module  425  coupled to fetch unit  420  to decode fetched elements. Fetch logic, in one embodiment, includes individual sequencers associated with thread slots  401   a ,  401   b , respectively. Usually core  401  is associated with a first ISA, which defines/specifies instructions executable on processor  400 . Often machine code instructions that are part of the first ISA include a portion of the instruction (referred to as an opcode), which references/specifies an instruction or operation to be performed. Decode logic  425  includes circuitry that recognizes these instructions from their opcodes and passes the decoded instructions on in the pipeline for processing as defined by the first ISA. For example, decoders  425 , in one embodiment, include logic designed or adapted to recognize specific instructions, such as transactional instruction. As a result of the recognition by decoders  425 , the architecture or core  401  takes specific, predefined actions to perform tasks associated with the appropriate instruction. It is important to note that any of the tasks, blocks, operations, and methods described herein may be performed in response to a single or multiple instructions; some of which may be new or old instructions. 
     In one example, allocator and renamer block  430  includes an allocator to reserve resources, such as register files to store instruction processing results. However, threads  401   a  and  401   b  are potentially capable of out-of-order execution, where allocator and renamer block  430  also reserves other resources, such as reorder buffers to track instruction results. Unit  430  may also include a register renamer to rename program/instruction reference registers to other registers internal to processor  400 . Reorder/retirement unit  435  includes components, such as the reorder buffers mentioned above, load buffers, and store buffers, to support out-of-order execution and later in-order retirement of instructions executed out-of-order. 
     Scheduler and execution unit(s) block  440 , in one embodiment, includes a scheduler unit to schedule instructions/operation on execution units. For example, a floating point instruction is scheduled on a port of an execution unit that has an available floating point execution unit. Register files associated with the execution units are also included to store information instruction processing results. Exemplary execution units include a floating point execution unit, an integer execution unit, a jump execution unit, a load execution unit, a store execution unit, and other known execution units. 
     Lower level data cache and data translation buffer (D-TLB)  450  are coupled to execution unit(s)  440 . The data cache is to store recently used/operated on elements, such as data operands, which are potentially held in memory coherency states. The D-TLB is to store recent virtual/linear to physical address translations. As a specific example, a processor may include a page table structure to break physical memory into a plurality of virtual pages. 
     Here, cores  401  and  402  share access to higher-level or further-out cache  410 , which is to cache recently fetched elements. Note that higher-level or further-out refers to cache levels increasing or getting further away from the execution unit(s). In one embodiment, higher-level cache  410  is a last-level data cache—last cache in the memory hierarchy on processor  400 —such as a second or third level data cache. However, higher level cache  410  is not so limited, as it may be associated with or includes an instruction cache. A trace cache—a type of instruction cache—instead may be coupled after decoder  425  to store recently decoded traces. 
     In the depicted configuration, processor  400  also includes bus interface module  405  and a power controller  460 , which may perform power management in accordance with an embodiment of the present invention. In this scenario, bus interface  405  is to communicate with devices external to processor  400 , such as system memory and other components. 
     A memory controller  470  may interface with other devices such as one or many memories. In an example, bus interface  405  includes a ring interconnect with a memory controller for interfacing with a memory and a graphics controller for interfacing with a graphics processor. In an SoC environment, even more devices, such as a network interface, coprocessors, memory, graphics processor, and any other known computer devices/interface may be integrated on a single die or integrated circuit to provide small form factor with high functionality and low power consumption. 
     Referring now to  FIG.  5   , shown is a block diagram of a micro-architecture of a processor core in accordance with one embodiment of the present invention. As shown in  FIG.  5   , processor core  500  may be a multi-stage pipelined out-of-order processor. As seen in  FIG.  5   , core  500  includes front end units  510 , which may be used to fetch instructions to be executed and prepare them for use later in the processor pipeline. For example, front end units  510  may include a fetch unit  501 , an instruction cache  503 , and an instruction decoder  505 . In some implementations, front end units  510  may further include a trace cache, along with microcode storage as well as a micro-operation storage. Fetch unit  501  may fetch macro-instructions, e.g., from memory or instruction cache  503 , and feed them to instruction decoder  505  to decode them into primitives, i.e., micro-operations for execution by the processor. 
     Coupled between front end units  510  and execution units  520  is an out-of-order (OOO) engine  515  that may be used to receive the micro-instructions and prepare them for execution. More specifically OOO engine  515  may include various buffers to re-order micro-instruction flow and allocate various resources needed for execution, as well as to provide renaming of logical registers onto storage locations within various register files such as register file  530  and extended register file  535 . Register file  530  may include separate register files for integer and floating point operations. Extended register file  535  may provide storage for vector-sized units, e.g., 256 or 512 bits per register. For purposes of configuration, control, and additional operations, a set of machine specific registers (MSRs)  538  may also be present and accessible to various logic within core  500  (and external to the core). 
     Various resources may be present in execution units  520 , including, for example, various integer, floating point, and single instruction multiple data (SIMD) logic units, among other specialized hardware. For example, such execution units may include one or more arithmetic logic units (ALUs)  522  and one or more vector execution units  524 , among other such execution units. 
     Results from the execution units may be provided to retirement logic, namely a reorder buffer (ROB)  540 . More specifically, ROB  540  may include various arrays and logic to receive information associated with instructions that are executed. This information is then examined by ROB  540  to determine whether the instructions can be validly retired and result data committed to the architectural state of the processor, or whether one or more exceptions occurred that prevent a proper retirement of the instructions. Of course, ROB  540  may handle other operations associated with retirement. 
     As shown in  FIG.  5   , ROB  540  is coupled to a cache  550  which, in one embodiment may be a low level cache (e.g., an L1 cache) although the scope of the present invention is not limited in this regard. Also, execution units  520  can be directly coupled to cache  550 . From cache  550 , data communication may occur with higher level caches, system memory and so forth. While shown with this high level in the embodiment of  FIG.  5   , understand the scope of the present invention is not limited in this regard. For example, while the implementation of  FIG.  5    is with regard to an out-of-order machine such as of an Intel® x86 instruction set architecture (ISA), the scope of the present invention is not limited in this regard. That is, other embodiments may be implemented in an in-order processor, a reduced instruction set computing (RISC) processor such as an ARM-based processor, or a processor of another type of ISA that can emulate instructions and operations of a different ISA via an emulation engine and associated logic circuitry. 
     Referring now to  FIG.  6   , shown is a block diagram of a micro-architecture of a processor core in accordance with another embodiment. In the embodiment of  FIG.  6   , core  600  may be a low power core of a different micro-architecture, such as an Intel®. Atom™-based processor having a relatively limited pipeline depth designed to reduce power consumption. As seen, core  600  includes an instruction cache  610  coupled to provide instructions to an instruction decoder  615 . A branch predictor  605  may be coupled to instruction cache  610 . Note that instruction cache  610  may further be coupled to another level of a cache memory, such as an L2 cache (not shown for ease of illustration in  FIG.  6   ). In turn, instruction decoder  615  provides decoded instructions to an issue queue  620  for storage and delivery to a given execution pipeline. A microcode ROM  618  is coupled to instruction decoder  615 . 
     A floating point pipeline  630  includes a floating point register file  632  which may include a plurality of architectural registers of a given bit with such as 128, 256 or 512 bits. Pipeline  630  includes a floating point scheduler  634  to schedule instructions for execution on one of multiple execution units of the pipeline. In the embodiment shown, such execution units include an ALU  635 , a shuffle unit  636 , and a floating point adder  638 . In turn, results generated in these execution units may be provided back to buffers and/or registers of register file  632 . Of course understand while shown with these few example execution units, additional or different floating point execution units may be present in another embodiment. 
     An integer pipeline  640  also may be provided. In the embodiment shown, pipeline  640  includes an integer register file  642  which may include a plurality of architectural registers of a given bit with such as 128 or 256 bits. Pipeline  640  includes an integer scheduler  644  to schedule instructions for execution on one of multiple execution units of the pipeline. In the embodiment shown, such execution units include an ALU  645 , a shifter unit  646 , and a jump execution unit  648 . In turn, results generated in these execution units may be provided back to buffers and/or registers of register file  642 . Of course understand while shown with these few example execution units, additional or different integer execution units may be present in another embodiment. 
     A memory execution scheduler  650  may schedule memory operations for execution in an address generation unit  652 , which is also coupled to a TLB  654 . As seen, these structures may couple to a data cache  660 , which may be a L0 and/or L1 data cache that in turn couples to additional levels of a cache memory hierarchy, including an L2 cache memory. 
     To provide support for out-of-order execution, an allocator/renamer  670  may be provided, in addition to a reorder buffer  680 , which is configured to reorder instructions executed out of order for retirement in order. Although shown with this particular pipeline architecture in the illustration of  FIG.  6   , understand that many variations and alternatives are possible. 
     Note that in a processor having asymmetric cores, such as in accordance with the micro-architectures of  FIGS.  5  and  6   , workloads may be dynamically swapped between the cores for power management reasons, as these cores, although having different pipeline designs and depths, may be of the same or related ISA. Such dynamic core swapping may be performed in a manner transparent to a user application (and possibly kernel also). 
     Referring to  FIG.  7   , shown is a block diagram of a micro-architecture of a processor core in accordance with yet another embodiment. As illustrated in  FIG.  7   , a core  700  may include a multi-staged in-order pipeline to execute at very low power consumption levels. As one such example, processor  700  may have a micro-architecture in accordance with an ARM Cortex A53 design available from ARM Holdings, LTD., Sunnyvale, Calif. In an implementation, an 8-stage pipeline may be provided that is configured to execute both 32-bit and 64-bit code. Core  700  includes a fetch unit  710  that is configured to fetch instructions and provide them to a decode unit  715 , which may decode the instructions, e.g., macro-instructions of a given ISA such as an ARMv8 ISA. Note further that a queue  730  may couple to decode unit  715  to store decoded instructions. Decoded instructions are provided to an issue logic  725 , where the decoded instructions may be issued to a given one of multiple execution units. 
     With further reference to  FIG.  7   , issue logic  725  may issue instructions to one of multiple execution units. In the embodiment shown, these execution units include an integer unit  735 , a multiply unit  740 , a floating point/vector unit  750 , a dual issue unit  760 , and a load/store unit  770 . The results of these different execution units may be provided to a writeback unit  780 . Understand that while a single writeback unit is shown for ease of illustration, in some implementations separate writeback units may be associated with each of the execution units. Furthermore, understand that while each of the units and logic shown in  FIG.  7    is represented at a high level, a particular implementation may include more or different structures. A processor designed using one or more cores having a pipeline as in  FIG.  7    may be implemented in many different end products, extending from mobile devices to server systems. 
     Referring to  FIG.  8   , shown is a block diagram of a micro-architecture of a processor core in accordance with a still further embodiment. As illustrated in  FIG.  8   , a core  800  may include a multi-stage multi-issue out-of-order pipeline to execute at very high performance levels (which may occur at higher power consumption levels than core  700  of  FIG.  7   ). As one such example, processor  800  may have a microarchitecture in accordance with an ARM Cortex A57 design. In an implementation, a 15 (or greater)-stage pipeline may be provided that is configured to execute both 32-bit and 64-bit code. In addition, the pipeline may provide for 3 (or greater)-wide and 3 (or greater)-issue operation. Core  800  includes a fetch unit  810  that is configured to fetch instructions and provide them to a decoder/renamer/dispatcher  815 , which may decode the instructions, e.g., macro-instructions of an ARMv8 instruction set architecture, rename register references within the instructions, and dispatch the instructions (eventually) to a selected execution unit. Decoded instructions may be stored in a queue  825 . Note that while a single queue structure is shown for ease of illustration in  FIG.  8   , understand that separate queues may be provided for each of the multiple different types of execution units. 
     Also shown in  FIG.  8    is an issue logic  830  from which decoded instructions stored in queue  825  may be issued to a selected execution unit. Issue logic  830  also may be implemented in a particular embodiment with a separate issue logic for each of the multiple different types of execution units to which issue logic  830  couples. 
     Decoded instructions may be issued to a given one of multiple execution units. In the embodiment shown, these execution units include one or more integer units  835 , a multiply unit  840 , a floating point/vector unit  850 , a branch unit  860 , and a load/store unit  870 . In an embodiment, floating point/vector unit  850  may be configured to handle SIMD or vector data of 128 or 256 bits. Still further, floating point/vector execution unit  850  may perform IEEE-754 double precision floating-point operations. The results of these different execution units may be provided to a writeback unit  880 . Note that in some implementations separate writeback units may be associated with each of the execution units. Furthermore, understand that while each of the units and logic shown in  FIG.  8    is represented at a high level, a particular implementation may include more or different structures. 
     Note that in a processor having asymmetric cores, such as in accordance with the micro-architectures of  FIGS.  7  and  8   , workloads may be dynamically swapped for power management reasons, as these cores, although having different pipeline designs and depths, may be of the same or related ISA. Such dynamic core swapping may be performed in a manner transparent to a user application (and possibly kernel also). 
     A processor designed using one or more cores having pipelines as in any one or more of  FIGS.  5 - 8    may be implemented in many different end products, extending from mobile devices to server systems. Referring now to  FIG.  9   , shown is a block diagram of a processor in accordance with another embodiment of the present invention. In the embodiment of  FIG.  9   , processor  900  may be a SoC including multiple domains, each of which may be controlled to operate at an independent operating voltage and operating frequency. As a specific illustrative example, processor  900  may be an Intel® Architecture Core™-based processor such as an i3, i5, i7 or another such processor available from Intel Corporation. However, other low power processors such as available from Advanced Micro Devices, Inc. (AMD) of Sunnyvale, Calif., an ARM-based design from ARM Holdings, Ltd. or licensee thereof or a MIPS-based design from MIPS Technologies, Inc. of Sunnyvale, Calif. or a RISC-V-based design, or their licensees or adopters may instead be present in other embodiments such as an Apple A9 processor, a Qualcomm Snapdragon processor, or Texas Instruments OMAP processor. Such SoC may be used in a low power system such as a smartphone, tablet computer, phablet computer, Ultrabook™ computer or other portable computing device or connected device. 
     In the high level view shown in  FIG.  9   , processor  900  includes a plurality of core units  910   0 - 910   n . Each core unit may include one or more processor cores, one or more cache memories and other circuitry. Each core unit  910  may support one or more instructions sets (e.g., an x86 instruction set (with some extensions that have been added with newer versions); a MIPS instruction set; an ARM instruction set (with optional additional extensions such as NEON)) or other instruction set or combinations thereof. Note that some of the core units may be heterogeneous resources (e.g., of a different design). In addition, each such core may be coupled to a cache memory (not shown) which in an embodiment may be a shared level (L2) cache memory. A non-volatile storage  930  may be used to store various program and other data. For example, this storage may be used to store at least portions of microcode, boot information such as a BIOS, other system software or so forth. 
     Each core unit  910  may also include an interface such as a bus interface unit to enable interconnection to additional circuitry of the processor. In an embodiment, each core unit  910  couples to a coherent fabric that may act as a primary cache coherent on-die interconnect that in turn couples to a memory controller  935 . In turn, memory controller  935  controls communications with a memory such as a DRAM (not shown for ease of illustration in  FIG.  9   ). 
     In addition to core units, additional processing engines are present within the processor, including at least one graphics unit  920  which may include one or more graphics processing units (GPUs) to perform graphics processing as well as to possibly execute general purpose operations on the graphics processor (so-called GPGPU operation). In addition, at least one image signal processor  925  may be present. Signal processor  925  may be configured to process incoming image data received from one or more capture devices, either internal to the SoC or off-chip. 
     Other accelerators also may be present. In the illustration of  FIG.  9   , a video coder  950  may perform coding operations including encoding and decoding for video information, e.g., providing hardware acceleration support for high definition video content. A display controller  955  further may be provided to accelerate display operations including providing support for internal and external displays of a system. In addition, a security processor  945  may be present to perform security operations such as secure boot operations, various cryptography operations and so forth. 
     Each of the units may have its power consumption controlled via a power manager  940 , which may include control logic to perform the various power management techniques described herein. 
     In some embodiments, SoC  900  may further include a non-coherent fabric coupled to the coherent fabric to which various peripheral devices may couple. One or more interfaces  960   a - 960   d  enable communication with one or more off-chip devices. Such communications may be via a variety of communication protocols such as PCIe™, GPIO, USB, I 2 C, UART, MIPI, SDIO, DDR, SPI, HDMI, among other types of communication protocols. Although shown at this high level in the embodiment of  FIG.  9   , understand the scope of the present invention is not limited in this regard. 
     Referring now to  FIG.  10   , shown is a block diagram of a representative SoC. In the embodiment shown, SoC  1000  may be a multi-core SoC configured for low power operation to be optimized for incorporation into a smartphone or other low power device such as a tablet computer or other portable computing device. As an example, SoC  1000  may be implemented using asymmetric or different types of cores, such as combinations of higher power and/or low power cores, e.g., out-of-order cores and in-order cores. In different embodiments, these cores may be based on an Intel® Architecture™ core design or an ARM architecture design. In yet other embodiments, a mix of Intel® and ARM cores may be implemented in a given SoC. 
     As seen in  FIG.  10   , SoC  1000  includes a first core domain  1010  having a plurality of first cores  1012   s - 1012   d . In an example, these cores may be low power cores such as in-order cores. In one embodiment these first cores may be implemented as ARM Cortex A53 cores. In turn, these cores couple to a cache memory  1015  of core domain  1010 . In addition, SoC  1000  includes a second core domain  1020 . In the illustration of  FIG.  10   , second core domain  1020  has a plurality of second cores  1022   a - 1022   d . In an example, these cores may be higher power-consuming cores than first cores  1012 . In an embodiment, the second cores may be out-of-order cores, which may be implemented as ARM Cortex A57 cores. In turn, these cores couple to a cache memory  1025  of core domain  1020 . Note that while the example shown in  FIG.  10    includes 4 cores in each domain, understand that more or fewer cores may be present in a given domain in other examples. 
     With further reference to  FIG.  10   , a graphics domain  1030  also is provided, which may include one or more graphics processing units (GPUs) configured to independently execute graphics workloads, e.g., provided by one or more cores of core domains  1010  and  1020 . As an example, GPU domain  1030  may be used to provide display support for a variety of screen sizes, in addition to providing graphics and display rendering operations. 
     As seen, the various domains couple to a coherent interconnect  1040 , which in an embodiment may be a cache coherent interconnect fabric that in turn couples to an integrated memory controller  1050 . Coherent interconnect  1040  may include a shared cache memory, such as an L3 cache, in some examples. In an embodiment, memory controller  1050  may be a direct memory controller to provide for multiple channels of communication with an off-chip memory, such as multiple channels of a DRAM (not shown for ease of illustration in  FIG.  10   ). 
     In different examples, the number of the core domains may vary. For example, for a low power SoC suitable for incorporation into a mobile computing device, a limited number of core domains such as shown in  FIG.  10    may be present. Still further, in such low power SoCs, core domain  1020  including higher power cores may have fewer numbers of such cores. For example, in one implementation two cores  1022  may be provided to enable operation at reduced power consumption levels. In addition, the different core domains may also be coupled to an interrupt controller to enable dynamic swapping of workloads between the different domains. 
     In yet other embodiments, a greater number of core domains, as well as additional optional IP logic may be present, in that an SoC can be scaled to higher performance (and power) levels for incorporation into other computing devices, such as desktops, servers, high performance computing systems, base stations forth. As one such example, 4 core domains each having a given number of out-of-order cores may be provided. Still further, in addition to optional GPU support (which as an example may take the form of a GPGPU), one or more accelerators to provide optimized hardware support for particular functions (e.g. web serving, network processing, switching or so forth) also may be provided. In addition, an input/output interface may be present to couple such accelerators to off-chip components. 
     Referring now to  FIG.  11   , shown is a block diagram of another example SoC. In the embodiment of  FIG.  11   , SoC  1100  may include various circuitry to enable high performance for multimedia applications, communications and other functions. As such, SoC  1100  is suitable for incorporation into a wide variety of portable and other devices, such as smartphones, tablet computers, smart TVs and so forth. In the example shown, SoC  1100  includes a central processor unit (CPU) domain  1110 . In an embodiment, a plurality of individual processor cores may be present in CPU domain  1110 . As one example, CPU domain  1110  may be a quad core processor having 4 multithreaded cores. Such processors may be homogeneous or heterogeneous processors, e.g., a mix of low power and high power processor cores. 
     In turn, a GPU domain  1120  is provided to perform advanced graphics processing in one or more GPUs to handle graphics and compute APIs. A DSP unit  1130  may provide one or more low power DSPs for handling low-power multimedia applications such as music playback, audio/video and so forth, in addition to advanced calculations that may occur during execution of multimedia instructions. In turn, a communication unit  1140  may include various components to provide connectivity via various wireless protocols, such as cellular communications (including 3G/4G LTE), wireless local area protocols such as Bluetooth™, IEEE 802.11, and so forth. 
     Still further, a multimedia processor  1150  may be used to perform capture and playback of high definition video and audio content, including processing of user gestures. A sensor unit  1160  may include a plurality of sensors and/or a sensor controller to interface to various off-chip sensors present in a given platform. An image signal processor  1170  may be provided with one or more separate ISPs to perform image processing with regard to captured content from one or more cameras of a platform, including still and video cameras. 
     A display processor  1180  may provide support for connection to a high definition display of a given pixel density, including the ability to wirelessly communicate content for playback on such display. Still further, a location unit  1190  may include a GPS receiver with support for multiple GPS constellations to provide applications highly accurate positioning information obtained using as such GPS receiver. Understand that while shown with this particular set of components in the example of  FIG.  11   , many variations and alternatives are possible. 
     Referring now to  FIG.  12   , shown is a block diagram of an example system with which embodiments can be used. As seen, system  1200  may be a smartphone or other wireless communicator. A baseband processor  1205  is configured to perform various signal processing with regard to communication signals to be transmitted from or received by the system. In turn, baseband processor  1205  is coupled to an application processor  1210 , which may be a main CPU of the system to execute an OS and other system software, in addition to user applications such as many well-known social media and multimedia apps. Application processor  1210  may further be configured to perform a variety of other computing operations for the device and perform the power management techniques described herein. 
     In turn, application processor  1210  can couple to a user interface/display  1220 , e.g., a touch screen display. In addition, application processor  1210  may couple to a memory system including a non-volatile memory, namely a flash memory  1230  and a system memory, namely a dynamic random access memory (DRAM)  1235 . As further seen, application processor  1210  further couples to a capture device  1245  such as one or more image capture devices that can record video and/or still images. 
     Still referring to  FIG.  12   , a universal integrated circuit card (UICC)  1240  comprising a subscriber identity module and possibly a secure storage and cryptoprocessor is also coupled to application processor  1210 . System  1200  may further include a security processor  1250  that may couple to application processor  1210 . A plurality of sensors  1225  may couple to application processor  1210  to enable input of a variety of sensed information such as accelerometer and other environmental information. An audio output device  1295  may provide an interface to output sound, e.g., in the form of voice communications, played or streaming audio data and so forth. 
     As further illustrated, a near field communication (NFC) contactless interface  1260  is provided that communicates in a NFC near field via an NFC antenna  1265 . While separate antennae are shown in  FIG.  12   , understand that in some implementations one antenna or a different set of antennae may be provided to enable various wireless functionality. 
     A PMIC  1215  couples to application processor  1210  to perform platform level power management. To this end, PMIC  1215  may issue power management requests to application processor  1210  to enter certain low power states as desired. Furthermore, based on platform constraints, PMIC  1215  may also control the power level of other components of system  1200 . 
     To enable communications to be transmitted and received, various circuitry may be coupled between baseband processor  1205  and an antenna  1290 . Specifically, a radio frequency (RF) transceiver  1270  and a wireless local area network (WLAN) transceiver  1275  may be present. In general, RF transceiver  1270  may be used to receive and transmit wireless data and calls according to a given wireless communication protocol such as 3G or 4G wireless communication protocol such as in accordance with a code division multiple access (CDMA), global system for mobile communication (GSM), long term evolution (LTE) or other protocol. In addition a GPS sensor  1280  may be present. Other wireless communications such as receipt or transmission of radio signals, e.g., AM/FM and other signals may also be provided. In addition, via WLAN transceiver  1275 , local wireless communications can also be realized. 
     Referring now to  FIG.  13   , shown is a block diagram of another example system with which embodiments may be used. In the illustration of  FIG.  13   , system  1300  may be mobile low-power system such as a tablet computer, 2:1 tablet, phablet or other convertible or standalone tablet system. As illustrated, a SoC  1310  is present and may be configured to operate as an application processor for the device and perform the power management techniques described herein. 
     A variety of devices may couple to SoC  1310 . In the illustration shown, a memory subsystem includes a flash memory  1340  and a DRAM  1345  coupled to SoC  1310 . In addition, a touch panel  1320  is coupled to the SoC  1310  to provide display capability and user input via touch, including provision of a virtual keyboard on a display of touch panel  1320 . To provide wired network connectivity, SoC  1310  couples to an Ethernet interface  1330 . A peripheral hub  1325  is coupled to SoC  1310  to enable interfacing with various peripheral devices, such as may be coupled to system  1300  by any of various ports or other connectors. 
     In addition to internal power management circuitry and functionality within SoC  1310 , a PMIC  1380  is coupled to SoC  1310  to provide platform-based power management, e.g., based on whether the system is powered by a battery  1390  or AC power via an AC adapter  1395 . In addition to this power source-based power management, PMIC  1380  may further perform platform power management activities based on environmental and usage conditions. Still further, PMIC  1380  may communicate control and status information to SoC  1310  to cause various power management actions within SoC  1310 . 
     Still referring to  FIG.  13   , to provide for wireless capabilities, a WLAN unit  1350  is coupled to SoC  1310  and in turn to an antenna  1355 . In various implementations, WLAN unit  1350  may provide for communication according to one or more wireless protocols. 
     As further illustrated, a plurality of sensors  1360  may couple to SoC  1310 . These sensors may include various accelerometer, environmental and other sensors, including user gesture sensors. Finally, an audio codec  1365  is coupled to SoC  1310  to provide an interface to an audio output device  1370 . Of course understand that while shown with this particular implementation in  FIG.  13   , many variations and alternatives are possible. 
     Referring now to  FIG.  14   , shown is a block diagram of a representative computer system such as notebook, Ultrabook™ or other small form factor system. A processor  1410 , in one embodiment, includes a microprocessor, multi-core processor, multithreaded processor, an ultra low voltage processor, an embedded processor, or other known processing element. In the illustrated implementation, processor  1410  acts as a main processing unit and central hub for communication with many of the various components of the system  1400 . As one example, processor  1400  is implemented as a SoC. 
     Processor  1410 , in one embodiment, communicates with a system memory  1415 . As an illustrative example, the system memory  1415  is implemented via multiple memory devices or modules to provide for a given amount of system memory. 
     To provide for persistent storage of information such as data, applications, one or more operating systems and so forth, a mass storage  1420  may also couple to processor  1410 . In various embodiments, to enable a thinner and lighter system design as well as to improve system responsiveness, this mass storage may be implemented via a SSD or the mass storage may primarily be implemented using a hard disk drive (HDD) with a smaller amount of SSD storage to act as a SSD cache to enable non-volatile storage of context state and other such information during power down events so that a fast power up can occur on re-initiation of system activities. Also shown in  FIG.  14   , a flash device  1422  may be coupled to processor  1410 , e.g., via a serial peripheral interface (SPI). This flash device may provide for non-volatile storage of system software, including a basic input/output software (BIOS) as well as other firmware of the system. 
     Various input/output (I/O) devices may be present within system  1400 . Specifically shown in the embodiment of  FIG.  14    is a display  1424  which may be a high definition LCD or LED panel that further provides for a touch screen  1425 . In one embodiment, display  1424  may be coupled to processor  1410  via a display interconnect that can be implemented as a high performance graphics interconnect. Touch screen  1425  may be coupled to processor  1410  via another interconnect, which in an embodiment can be an I 2 C interconnect. As further shown in  FIG.  14   , in addition to touch screen  1425 , user input by way of touch can also occur via a touch pad  1430  which may be configured within the chassis and may also be coupled to the same I 2 C interconnect as touch screen  1425 . 
     For perceptual computing and other purposes, various sensors may be present within the system and may be coupled to processor  1410  in different manners. Certain inertial and environmental sensors may couple to processor  1410  through a sensor hub  1440 , e.g., via an I 2 C or I3C interconnect. In the embodiment shown in  FIG.  14   , these sensors may include an accelerometer  1441 , an ambient light sensor (ALS)  1442 , a compass  1443  and a gyroscope  1444 . Other environmental sensors may include one or more thermal sensors  1446  which in some embodiments couple to processor  1410  via a system management bus (SMBus) bus. 
     Also seen in  FIG.  14   , various peripheral devices may couple to processor  1410  via a low pin count (LPC) interconnect. In the embodiment shown, various components can be coupled through an embedded controller  1435 . Such components can include a keyboard  1436  (e.g., coupled via a PS2 interface), a fan  1437 , and a thermal sensor  1439 . In some embodiments, touch pad  1430  may also couple to EC  1435  via a PS2 interface. In addition, a security processor such as a trusted platform module (TPM)  1438  may also couple to processor  1410  via this LPC interconnect. 
     System  1400  can communicate with external devices in a variety of manners, including wirelessly. In the embodiment shown in  FIG.  14   , various wireless modules, each of which can correspond to a radio configured for a particular wireless communication protocol, are present. One manner for wireless communication in a short range such as a near field may be via a NFC unit  1445  which may communicate, in one embodiment with processor  1410  via an SMBus. Note that via this NFC unit  1445 , devices in close proximity to each other can communicate. 
     As further seen in  FIG.  14   , additional wireless units can include other short range wireless engines including a WLAN unit  1450  and a Bluetooth unit  1452 . Using WLAN unit  1450 , Wi-Fi™ communications can be realized, while via Bluetooth unit  1452 , short range Bluetooth™ communications can occur. These units may communicate with processor  1410  via a given link. 
     In addition, wireless wide area communications, e.g., according to a cellular or other wireless wide area protocol, can occur via a WWAN unit  1456  which in turn may couple to a subscriber identity module (SIM)  1457 . In addition, to enable receipt and use of location information, a GPS module  1455  may also be present. Note that in the embodiment shown in  FIG.  14   , WWAN unit  1456  and an integrated capture device such as a camera module  1454  may communicate via a given link. 
     An integrated camera module  1454  can be incorporated in the lid. To provide for audio inputs and outputs, an audio processor can be implemented via a digital signal processor (DSP)  1460 , which may couple to processor  1410  via a high definition audio (HDA) link. Similarly, DSP  1460  may communicate with an integrated coder/decoder (CODEC) and amplifier  1462  that in turn may couple to output speakers  1463  which may be implemented within the chassis. Similarly, amplifier and CODEC  1462  can be coupled to receive audio inputs from a microphone  1465  which in an embodiment can be implemented via dual array microphones (such as a digital microphone array) to provide for high quality audio inputs to enable voice-activated control of various operations within the system. Note also that audio outputs can be provided from amplifier/CODEC  1462  to a headphone jack  1464 . Although shown with these particular components in the embodiment of  FIG.  14   , understand the scope of the present invention is not limited in this regard. 
     Embodiments may be implemented in many different system types. Referring now to  FIG.  15   , shown is a block diagram of a system in accordance with an embodiment of the present invention. As shown in  FIG.  15   , multiprocessor system  1500  is a point-to-point interconnect system, and includes a first processor  1570  and a second processor  1580  coupled via a point-to-point interconnect  1550 . As shown in  FIG.  15   , each of processors  1570  and  1580  may be multicore processors, including first and second processor cores (i.e., processors  1574   a  and  1574   b  and processor cores  1584   a  and  1584   b ), although potentially many more cores may be present in the processors. Each of the processors can include a PCU  1575 ,  1585  to perform processor-based power management, including the static or dynamic control of voltage regulators, as described herein. 
     Still referring to  FIG.  15   , first processor  1570  further includes a memory controller hub (MCH)  1572  and point-to-point (P-P) interfaces  1576  and  1578 . Similarly, second processor  1580  includes a MCH  1582  and P-P interfaces  1586  and  1588 . As shown in  FIG.  15   , MCH&#39;s  1572  and  1582  couple the processors to respective memories, namely a memory  1532  and a memory  1534 , which may be portions of system memory (e.g., DRAM) locally attached to the respective processors. First processor  1570  and second processor  1580  may be coupled to a chipset  1590  via P-P interconnects  1576  and  1586 , respectively. As shown in  FIG.  15   , chipset  1590  includes P-P interfaces  1594  and  1598 . 
     Furthermore, chipset  1590  includes an interface  1592  to couple chipset  1590  with a high performance graphics engine  1538 , by a P-P interconnect  1539 . In turn, chipset  1590  may be coupled to a first bus  1516  via an interface  1596 . As shown in  FIG.  15   , various input/output (I/O) devices  1514  may be coupled to first bus  1516 , along with a bus bridge  1518  which couples first bus  1516  to a second bus  1520 . Various devices may be coupled to second bus  1520  including, for example, a keyboard/mouse  1522 , communication devices  1526  and a data storage unit  1528  such as a disk drive or other mass storage device which may include code  1530 , in one embodiment. Further, an audio I/O  1524  may be coupled to second bus  1520 . Embodiments can be incorporated into other types of systems including mobile devices such as a smart cellular telephone, tablet computer, netbook, Ultrabook™, or so forth. 
       FIG.  16    is a block diagram illustrating an IP core development system  1600  that may be used to manufacture an integrated circuit to perform operations according to an embodiment. The IP core development system  1600  may be used to generate modular, re-usable designs that can be incorporated into a larger design or used to construct an entire integrated circuit (e.g., an SoC integrated circuit). A design facility  1630  can generate a software simulation  1610  of an IP core design in a high level programming language (e.g., C/C++). The software simulation  1610  can be used to design, test, and verify the behavior of the IP core. A register transfer level (RTL) design can then be created or synthesized from the simulation model. The RTL design  1615  is an abstraction of the behavior of the integrated circuit that models the flow of digital signals between hardware registers, including the associated logic performed using the modeled digital signals. In addition to an RTL design  1615 , lower-level designs at the logic level or transistor level may also be created, designed, or synthesized. Thus, the particular details of the initial design and simulation may vary. 
     The RTL design  1615  or equivalent may be further synthesized by the design facility into a hardware model  1620 , which may be in a hardware description language (HDL), or some other representation of physical design data. The HDL may be further simulated or tested to verify the IP core design. The IP core design can be stored for delivery to a third party fabrication facility  1665  using non-volatile memory  1640  (e.g., hard disk, flash memory, or any non-volatile storage medium). Alternately, the IP core design may be transmitted (e.g., via the Internet) over a wired connection  1650  or wireless connection  1660 . The fabrication facility  1665  may then fabricate an integrated circuit that is based at least in part on the IP core design. The fabricated integrated circuit can be configured to perform operations in accordance with at least one embodiment described herein. 
     Referring now to  FIG.  17   , shown is a block diagram of a high level view of a processor in accordance with an embodiment. As shown in  FIG.  17   , processor  1700 , which may be a multicore processor or other SoC, includes a plurality of cores  1710   0 - 1710   7 . Although shown with 8 cores in this embodiment, in different embodiments 4, 16, 32 or some other number of cores may be present. In addition, a graphics processor  1720  also is present. Although shown as a single unit, understand that graphics processor  1720  may include multiple independent graphics processing units (GPUs). As additionally shown, a shared cache memory  1730  may be shared by cores  1710  and graphics processor  1720 . 
     In addition, processor  1700  also includes a power controller  1740  which may be used to provide overall power control for processor  1700 . In embodiments herein, power controller  1740  may include a location selective regulator controller  1745 , details of which will be described further herein. In addition, a memory controller  1750  may provide an interface between processor  1700  and a system memory, such as DRAM. 
     With further reference to  FIG.  17   , note that processor  1700  includes a plurality of LDOs  1760   0 - 1760   17 . In this implementation, the number of LDOs  1760  is oversubscribed with respect to the number of cores  1710  and graphics processor  1720 . That is, processor  1700  is fabricated with more LDOs than corresponding processing units. In the particular implementation shown, cores  1710  and graphics processor  1720  each may include at least one LDO  1760 . In addition, additional LDOs  1760  may be present externally to such processing units. These additional LDOs  1760  may, in some cases, act as auxiliary or substitute LDOs that may be controlled to provide power to one or more corresponding cores  1710  or other processing unit, depending upon configuration of the processor. Understand while in the embodiment of  FIG.  17   , each core in graphics processor is shown associated with two LDOs  1760  (one being internal to the corresponding processing unit and one external), embodiments are not limited in this regard and additional LDOs may be associated with particular cores or other processing units, such that possibly more than one LDO may be included within a given core and similarly more than one LDO may be externally located from a given core but associated with that core. 
     In an embodiment as in  FIG.  17    with an oversubscribed number of voltage regulators, power controller  1740  and more specifically location selective regulator controller  1745  may access fuse information associated with the voltage regulators. As illustrated, processor  1700  may include a fuse storage  1770 , e.g., implemented in a non-volatile memory that stores a variety of configuration information for processor  1700 . Of interest herein, fuse storage  1770  includes LDO configuration information  1775 . In an embodiment, LDO configuration information  1775  may store, e.g., a corresponding enable indicator or other information to identify, for each LDO, whether it is to be enabled or not. As such, in this static type of implementation, based on fuse information, certain LDOs  1760  may be statically disabled while others statically enabled. Such fuse information may be based on design time or post-manufacturing testing that identifies locations of likely thermal hot spots during operation. With this pre or post-silicon information, it may be used to cause certain LDOs  1760  to be enabled during operation while other such LDOs  1760  (e.g., associated with the identified likely hot spot regions) to be disabled. With LDOs as described herein in an oversubscription situation, the LDOs may be spaced throughout a processor, including internally to cores themselves, potentially with distributed power gates as described herein. 
     Further illustrated in  FIG.  17   , each core  1710   0 - 1710   7  may include or be associated with at least one thermal sensor  1712   0 - 1712   7 . Understand that additional thermal sensors, which in an embodiment may be implemented as thermal diodes or other such mechanisms, may be provided throughout a layout of processor  1700  to sense and provide thermal information, e.g., to power controller  1740 . Note that this thermal information may be used for various reasons, including the location selective control of LDOs as described herein. Also based on this thermal information, when it is determined that processor  1700  overall is operating at an excessive level, high level thermal regulation may be performed to protect the processor, e.g., by reducing operating voltage and/or frequency and/or shutting down subsystems or all of processor  1700 . In addition, when thermal information is used as a predicate for activity information, power controller  1740  may control power regulation appropriately to deliver needed current for a given task. Still further, the thermal information may be provided to location selective regulator controller  1745  for use in performing dynamic control of LDO enabling/disabling as described herein. 
     In a particular embodiment, a small intellectual property (IP) block, e.g., a relatively small low power core or other processing unit may include or be associated with a single LDO. Larger higher power consuming cores (e.g., out-of-order cores) may be associated with two LDOs. And in embodiments providing for oversubscription, one or more additional or substitute LDOs may be associated with the various cores or other processing units. Of course greater or fewer numbers of LDOs may be included in or otherwise associated with particular cores in other embodiments. 
     Note further that although in the high level shown in  FIG.  17   , LDOs  1760  are generally shown as being symmetrically located with respect to cores  1710 , such representation is for ease of illustration only. Instead, in many embodiments in which there are an oversubscribed number of LDOs, the LDOs may be asymmetrically located with regard to particular cores. Stated another way, the LDOs may be asymmetrically located throughout a semiconductor die to enable a selective one or more of the LDOs to provide power to corresponding cores and other processing units, either statically or dynamically in a manner to avoid or reduce hotspots. 
     In one embodiment, all of the components shown in  FIG.  17    may be implemented on a single semiconductor die. In other cases, at least some of the LDOs may be implemented on another semiconductor die in a stacked die configuration. Further, while shown with a particular high level arrangement that provides for oversubscription of LDOs, other embodiments may enable location selective-based voltage regulator control even without oversubscription of voltage regulators. 
     Note that in the high level view of  FIG.  17   , only a limited number of components within processor  1700  are illustrated. It is to be understood that additional compute and other processing engines, including other compute components, physical unit (PHY) circuits, and other uncore circuitry may be present. As with the above discussion, such components may in certain embodiments be associated with multiple LDOs  1760 , such that controllable power delivery to such components may occur as described herein. Understand while shown at this high level in the embodiment of  FIG.  17   , many variations and alternatives are possible. 
     Referring now to  FIG.  18   , shown is a block diagram of a core in accordance with an embodiment. As shown in  FIG.  18   , core  1800  may be any type of processing core such as a given in-order or out-of-order processor. In the high level shown in  FIG.  18   , core  1800  includes front end circuits  1810 , such as instruction fetch and decode units. In turn, front end unit circuits  1810  couple to a plurality of execution circuits  1820 , which may execute instructions or other operations. In turn, results generated in execution circuits  1820  may be provided to back end circuits  1830  such as a retirement unit or so forth. As further shown, one or more cache memories  1840  may couple to the various circuits. 
     With regard to location-based selective power control as described herein, core  1800  further includes an LDO  1850 . Note that LDO  1850  is configured to receive a reference voltage corresponding to regulated voltage level from a power management agent  1860 . In turn, power management agent  1860  may be in communication with a PCU of the processor. In addition, power management agent  1860  may further receive performance monitoring information from a performance monitor circuit  1870 . In embodiments herein, performance monitor circuit  1870  may maintain information regarding performance and activity within core  1800 . For example, a variety of performance monitors or other activity counters may be provided to maintain information regarding activity within individual units within core  1800 . In addition, performance monitor circuit  1870  may in some cases receive environmental information from sensors within core  1800 , including thermal sensors such as thermal sensors  1812 ,  1822  and  1832 . Based on this information, performance monitor circuit  1870  may provide an indication of activity levels of particular units within core  1800  both to power management agent  1860  and LDO  1850 . In turn, this information may be used by various agents to control LDO  1850  and its associated power gate circuitry based thereon. 
     Based at least in part on this activity information, LDO  1850  may send gate control signals to its associated power gate modules  1855   0 - 1855   n . Note that each power gate module  1855  may include one or more power gate circuits of LDO  1850 . And as shown, these power gates may be distributed throughout an area of core  1800  so that their thermal effects also may be distributed. Further in embodiments herein, with fine granularity information as to activity levels that may exceed a given activity or thermal threshold, LDO  1850  may disable gate control signals to at least a subset of power gate modules  1855  that are more closely located with components of core  1850  undergoing a hot spot or other thermal condition can be disabled, to allow greater thermal dissipation. Understand while shown at this high level in the embodiment of  FIG.  18   , many variations and alternatives are possible. 
     Referring now to  FIG.  19   , shown is a schematic diagram of a LDO in accordance with an embodiment of the present invention. As shown in  FIG.  19   , LDO  1900  includes a comparator  1910  that compares a reference voltage (namely a target regulated voltage) to a feedback voltage, which may be received via an impedance  1915  (e.g., a voltage divider), such that the feedback voltage is based on the output voltage generated by LDO  1900 . In an embodiment, comparator  1910  may be implemented with one or more analog-to-digital converters (ADCs) that receive the feedback voltage and one of a plurality of selected reference voltages, e.g., as selected by a selector  1905  based on a reference voltage control signal, which may be sent by a power controller, to indicate an appropriate voltage level at which the LDO is to operate. 
     As further illustrated, the output of comparator  1910  is provided to a controller  1920 . In embodiments herein, controller  1920  may further receive an enable signal that enables the LDO for operation. Conversely, when the enable signal is disabled, LDO  1900  may, as a whole, be disabled. As further shown, controller  1920  may further receive activity information, such as thermal information to indicate a location of any hot spots within core  1800 . As such, controller  1920  may, based at least in part on this information, selectively determine a number and location of corresponding power gate circuits to enable or disable. More specifically as shown in  FIG.  19   , a plurality of power gate modules  1930   0 - 1930   n  are present. As illustrated, each power gate modules  1930  may include a plurality of metal oxide semiconductor field effect transistors (namely NMOSs M 0 -MN) that when enabled by gate control signals output an input voltage (e.g., received from an on-chip or off-chip voltage source) to provide an output voltage. 
     Note that in the implementation of  FIG.  19   , power gate circuitry is thus arranged as a plurality of power gate modules  1930   0 - 1930   y . As shown, each power gate module  1930  may include multiple NMOSs M 0 -MN. To effect control of appropriate ones of these NMOS devices, controller  1920  may output an N-bit gate control signal to each of the plurality of power gate modules  1930   0 - 1930   y . As one particular example, each power gate module  1930  may include five switching elements; of course, different numbers of individual switching elements per module may be realized. 
     In a representative example, each power gate module  1930  may provide a given total minimum resistance. In some cases, multiple power gate modules  1930  may be associated with each core. For example, in one embodiment each core may be associated with one or more LDOs each having at least two power gate modules  1930  to provide location selective control of power distribution. In another case, many more power gate modules  1930  may be provided per core. As one such example, 16 power gate modules  1930  may be provided per core. In such instance, each such power gate module  1930  may provide a total minimum resistance of approximately 8 milliohms. With such implementation, power gate modules  1930  may be distributed throughout a layout of a core to selectively control enabling/disabling of the power gates of respective power gate modules  1930 , e.g., based on hot spot information of the core. 
     Thus in embodiments, each power gate module  1930  may be distributed within a different region of a given processing circuit. In some cases, individual power gates formed of corresponding NMOS switching devices also may be physically distributed, or all NMOSs of a given power gate module  1930  may be closely located to each other. Based on the activity information and appropriate enabling of thermal-based-control as described herein, each power gate module  1930  may be individually controlled, in which each of its multiple constituent individual power gates M 0 -MN can be individually controlled via a multi-bit gate control signal, provided to each of power gate module  1930 . Note that each power gate module  1930  may be independently addressed by controller  1920 . Understand while shown with this particular implementation in the embodiment of  FIG.  19   , many variations and alternatives are possible. 
     As discussed above, in some embodiments at least some of the voltage regulators may be adapted on a different semiconductor die than the cores or other processing units. Referring now to  FIG.  20   , shown is a cross-sectional view of a processor in accordance with an embodiment. As illustrated in  FIG.  20   , processor  2000 , which may be a multicore processor or other SoC, includes multiple semiconductor die that are stacked together, namely a first semiconductor die  2010 , a second semiconductor die  2020  and a third semiconductor die  2030 . In the embodiment shown in  FIG.  20   , first semiconductor die  2010  may include a plurality of cores  2012   0 - 2012   n . Although only two such cores are shown for ease of illustration, understand that many more cores, other processing units and additional circuitry may be present in a particular embodiment. As further shown, first semiconductor die  2010  also includes a GPU  2015 . 
     In turn, second semiconductor die  2020  includes a plurality of LDOs  2022   0 - 2022   n . Second die  2020  may further include additional components such as additional compute circuits, physical unit circuits and so forth. In a particular embodiment shown in  FIG.  20   , second semiconductor die  2020  includes at least one PHY circuit  2026  and at least one additional compute circuit  2028 , which in an example may be a boot core (such as a microcontroller) to configure and bring up the system or a sensor hub to provide a fusion of environmental data such as gyroscopic information, compass information, barometer information, accelerometer information, GPS information, magnetic sensor information and so forth. Note that such circuitry and second semiconductor die  2020  overall may be the first die to power up and initialize activity, and may have capabilities to operate at lower power levels than first semiconductor die  2010 . Note that multiple die influence the thermals of each other. If bottom die  2020  becomes hot, it will heat up die  2010  (and possibly die  2030 ) above, and vice versa. And of course this will change dynamically, depending the currently run workload. 
     Note that depending on implementation, one or more oversubscribed LDOs  2025  also may be present (shown in dashed form in  FIG.  20   ). Whether or not an implementation provides for oversubscription, note that location selective control of LDOs  2022 ,  2025  may occur so that an LDO directly under a core  2012  having a hot spot may be controlled to be disabled or at least to have some number of its constituent power gates turned off. And further with an arrangement as in  FIG.  20   , when GPU  2015  is inactive, LDO  2025 , which may provide primary power to GPU  2015 , may provide additional current (or all required current) to one or more cores  2012 . As further illustrated in  FIG.  20   , third semiconductor die  2030  may be a memory die which can be implemented as an example with DRAM or another memory topology such as a non-volatile dual inline memory module (NVDIMM). 
     Referring now to  FIG.  21   , shown is a flow diagram of a method in accordance with an embodiment of the present invention. As shown in  FIG.  21   , method  2100  is a method for controlling voltage regulators of a processor or other SoC as described herein. As such, method  2100  may be performed by hardware circuitry, firmware, software and/or combinations thereof. In a particular embodiment, method  2100  may be performed by a location selective regulator controller which may be implemented, in an embodiment, within a power controller of a processor. As seen, method  2100  begins by powering cores with default voltage regulators (block  2110 ). Note that while  FIG.  21    is in the context of a multicore processor, understand that in addition to or instead of cores, additional or different processing units may similarly be powered by one or more selected voltage regulators. In block  2110 , such default voltage regulators may be a primary voltage regulator with which a given core is associated, e.g., in a map table that includes a plurality of entries each to identify at least one primary voltage regulator that is to provide a regulated voltage to a given core, as well as one or more secondary or substitute voltage regulators that optionally may provide some or all of a regulated voltage to a given core. In some cases this map table may be implemented within fuse storage or other non-volatile storage of the processor. 
     In any event, a processor may thus begin operation with power being provided to cores from default voltage regulators. In some cases there may be a 1:1 correspondence between a primary voltage regulator and a corresponding core. In other cases, multiple voltage regulators may act as a primary voltage regulator for a given core. 
     Next it is determined whether thermal information from any region of the processor exceeds a thermal threshold (diamond  2120 ). As an example, a processor die may be partitioned into a plurality of segments, e.g., quadrants, where each quadrant includes at least one core. Assume for purposes of discussion herein that a first region is operating at a temperature that exceeds this thermal threshold. As such, control next passes to block  2130  where this region may be identified. Then at block  2140  a map table may be accessed. More specifically, an entry of the map table associated with this region (or multiple such entries each associated with a core present in this region) may be used to identify one or more substitute voltage regulators for the region. Thereafter at block  2150  such substitute voltage regulators may be enabled to provide power to the core or cores present in this identified region having a hot spot. Note that in some cases, this substitute voltage regulator may provide some of the power to the core or cores of this region, and the primary voltage regulator may continue to provide some of the power, but with a reduced number of active power gates to reduce the thermal load. In other cases, the primary voltage regulator may be fully disabled to allow for greater thermal dissipation and temperature reduction. 
     Still with reference to  FIG.  21   , control next passes to block  2160  where a threshold time may then occur. Although embodiments are not limited in this regard as an example, this threshold time may be on the order of between tens of milliseconds and one or more seconds. Note that it is possible that power gates in a hot region are still used in reacting to a major transient (so the power gates are on for a few nanoseconds). When a controller determines the number of power gates to turn on, the ones in the hot region will be the last to be turned on. In the case where all FETs are on, the processor may limit such operation to less than a given duration, e.g., 10 milliseconds. 
     Such threshold time thus allows the potential for cooling of any identified hot spots. Next after this threshold time has completed, control passes to diamond  2170  where it may be determined whether thermal information of any identified region (previously having a hot spot) exceeds the thermal threshold. If so, control passes to block  2180  where a frequency reduction (and optionally a voltage reduction) of one or more cores, such as the cores associated with the identified region(s), may occur to reduce a performance state. As such, this parameter change and throttling of activity may enable sufficient reduction in temperature. As illustrated, after this change, control passes to block  2160 , discussed above. Note of course that after the thermal issue is resolved, such throttle mechanisms may be removed, enabling the throttled cores or other circuitry to increase their performance state. 
     Otherwise if it is determined that as a result of this different configuration of power supply associations that temperature of the regions has reduced, control may pass back to block  2110 , where a default configuration of voltage regulators to cores may again be applied. Of course such return to default configuration need not necessarily occur in all embodiments. Furthermore, understand that the arrangement in  FIG.  21    may be used both in cases where there is an oversubscription of voltage regulators with respect to cores and cases where there are not extra voltage regulators. Nevertheless, even without oversubscription, the dynamic control described in  FIG.  21    may be used to power given cores from a combination of voltage regulators and/or a controllable amount of power gates of a given one or more voltage regulator. 
     Also understand that while this embodiment describes an arrangement in which there is at least one core per quadrant, embodiments are not limited in this aspect. In other cases, one or more quadrants may include other circuitry instead of cores. For example, a given quadrant may include a high speed multi-physical unit (PHY) with a phase lock loop that may be provided with independent power control. And of course, any other type of IP circuit, such as a neural network or so forth may be present in a given quadrant in addition to or instead of one or more cores. Understand while shown at this high level in the embodiment of  FIG.  21   , many variations and alternatives are possible. 
     Referring now to  FIG.  22   , shown is a flow diagram of a method in accordance with another embodiment of the present invention. Specifically, method  2200  is a more particular method for controller at least one LDO associated with a core, at a regional granularity of the core. As such, method  2200  may be performed by hardware circuitry, firmware, software and/or combinations thereof. In a particular embodiment, method  2200  may be performed by control circuitry included in or associated with an LDO, and/or a local power controller such as a power management agent of a given core. 
     As illustrated, method  2200  begins by powering a core with an operating voltage from distributed power gates of at least one LDO (block  2210 ). Note that this LDO may be a locally present LDO, e.g., present within the circuitry of the core itself. Or it can be an LDO otherwise associated with the core, e.g., as present on the same semiconductor die as the core or on a separate core as described herein. 
     During operation, performance monitoring information of the core may be received (block  2220 ). In an embodiment, the core may include performance monitors as described herein, which may maintain information regarding activity of the core. Based at least in part on this information it may be determined at diamond  2230  whether the activity level exceeds an activity threshold. In some cases, performance monitoring information in the form of instructions per cycle or so forth may be considered with respect to an activity threshold, also in terms of instructions per cycle or so forth. In other cases, the activity level may correspond to temperature information associated with one or more temperature sensors of the core and the activity threshold may be a given temperature threshold. 
     In any case, if it is determined that the activity level exceeds an activity threshold control passes to block  2240  where a region of the core may be identified that is associated with this high activity level. For example, a core itself may be segmented into different regions and based on an activity of the different regions, a hot spot region within the core can be identified. Next, it is determined at diamond  2250  whether a current load is less than a current threshold. This current load may correspond to a given current level at which the core is operating. In some cases, this current level may in terms of a percentage of power gates to be enabled to provide sufficient power for a given current consumption level. For example, in some cases, this current level may in terms of a percentage of power gates to be enabled to provide sufficient power for a given current consumption level. For example, to operate a core at 10 amperes (A), approximately 10% of the power gates of a given LDO may be enabled. In almost all cases only a fraction of the power gates are enabled. Typically, an IP circuit runs at approximately half of its peak current. In a scenario where the IP circuit is running at 10 A and has a peak current of 20 A, 9% of the power gates (implemented as FETs) are enabled. Even at 18 A typical/20 A peak, only 50% of the power gates are on. Table 1 illustrates some examples. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 Example 1a: 
                 Example 2: 
               
               
                   
                   
                   
                   
                 Changing 
                 Changing 
               
               
                   
                   
                   
                   
                 operating 
                 Load line 
               
               
                 Column 
                 Calculation 
                   
                 Example 1 
                 current 
                 (LL) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 A 
                   
                 Minimum LDO resistance 
                 0.5 
                 0.5 
                 0.5 
               
               
                   
                   
                 (mOhms) 
                   
                   
                   
               
               
                 B 
                   
                 Total LL not including 
                 4.5 
                 4.5 
                 9.5 
               
               
                   
                   
                 LDO (mOhms) 
                   
                   
                   
               
               
                 C 
                   
                 Peak current 
                 20 
                 20 
                 20 
               
               
                 D 
                   
                 typical current 
                 10 
                 18 
                 10 
               
               
                 E 
                 C * (B + A) 
                 Voltage drop at max 
                 100 
                 100 
                 200 
               
               
                   
                   
                 current (mV) 
                   
                   
                   
               
               
                 F 
                 (E − (B * D))/D 
                 LDO Resistance needed 
                 5.50 
                 1.06 
                 10.50 
               
               
                   
                   
                 to keep Voltage drop 
                   
                   
                   
               
               
                   
                   
                 constant at typical 
                   
                   
                   
               
               
                   
                   
                 current (mOhms) 
                   
                   
                   
               
               
                 G 
                 min R/actual R 
                 Percentage of LDOs 
                 9% 
                 47% 
                 5% 
               
               
                   
                   
                 on during typical 
                   
                   
                   
               
               
                   
                   
                 currents 
               
               
                   
               
            
           
         
       
     
     As another representative example, assume an LDO is to operate with an input voltage of approximately 1.0 volts and to provide a regulated output voltage of approximately 0.9 volts. Further assume that the circuitry to be powered by this regulated voltage has a current consumption level of approximately 10 amperes. In this situation, a given percentage of power gates may be enabled to provide a total resistance of, e.g., 10 milliohms. Assume further that due to increased current consumption, e.g., as a result of increased activity such as enabling of additional core portions such as one or more vector execution units, the current consumption level increases to 20 amperes. In this situation, the resistance provided by the power gates may be dropped, e.g., to 5 milliohms to maintain the regulated output voltage at the requested level. 
     Still with reference to  FIG.  22   , in a particular embodiment, this current threshold may correspond to a level of approximately 80% of power gates being enabled. As an example, this current threshold may be set at a level of 80% of power gates being active. If lower than the threshold level of active power gates exists, one or more power gates of the identified region may be disabled (block  2260 ). That is, as the core is operating at a current load that can be handled with fewer power gates, one or more power gates in the identified region can be disabled, to reduce thermal load. 
     Otherwise, if the current load exceeds the current threshold, the previous voltage regulator settings, including a number of enabled power gates, may continue. This is the case, as it is likely that the high current demanded by the core is likely to only exist for thermally insignificant time durations (e.g., on the order of a few milliseconds). As such, the voltage regulator can continue to operate with its current configuration and not harm the processor. Understand while shown at this high level in the embodiment of  FIG.  22   , many variations and alternatives are possible. 
     The following examples pertain to further embodiments. 
     In one example, a processor comprises: a first plurality of IP circuits to execute operations; and a second plurality of integrated voltage regulators, where the second plurality of integrated voltage regulators are oversubscribed with respect to the first plurality of IP circuits. 
     In an example, the processor further comprises a fuse storage to store configuration information regarding the second plurality of integrated voltage regulators, the fuse storage to store a plurality of indicators, each to indicate whether a corresponding one of the second plurality of integrated voltage regulators is to be enabled. 
     In an example, one or more of the plurality of indicators is to indicate that a corresponding one of the second plurality of integrated voltage regulators is to be disabled based at least in part on post-silicon hot spot correlation information. 
     In an example, the processor further comprises a control circuit to receive the configuration information and disable at least in part one or more of the second plurality of integrated voltage regulators based at least in part thereon. 
     In an example, the processor comprises a first semiconductor die having the first plurality of IP circuits. 
     In an example, the first semiconductor die comprises a plurality of regions each including at least one of the first plurality of IP circuits, where when a temperature of a first region of the plurality of regions exceeds a thermal threshold, one or more of the second plurality of integrated voltage regulators associated with the first region are to be disabled. 
     In an example, the processor further comprises a second semiconductor die having the second plurality of integrated voltage regulators. 
     In an example, each of the second plurality of integrated voltages comprises a low drop out regulator including: a plurality of power gates to receive an input voltage and output a regulated voltage; and a controller to compare a feedback voltage of the regulated voltage to a reference voltage and send gate control signals to the plurality of power gates. 
     In an example, the controller is to receive activity information of at least a first IP circuit of the plurality of IP circuits and control a number of the plurality of power gates to be enabled based at least in part thereon. 
     In an example, the processor further comprises a control circuit to receive activity information of at least some of the first plurality of IP circuits and identify one or more of the second plurality of integrated voltage regulators to be disabled based at least in part thereon. 
     In an example, each of the first plurality of IP circuits is to couple to more than one of the second plurality of integrated voltage regulators. 
     In an example, the second plurality of integrated voltage regulators are asymmetrically located with regard to the first plurality of IP circuits. 
     In another example, a method comprises: causing a first integrated voltage regulator of a plurality of integrated voltage regulators of a processor to provide an operating voltage to a first core of a plurality of cores of the processor; and in response to determining that a temperature of a first region of the processor including the first core exceeds a temperature threshold, causing a second integrated voltage regulator to provide at least a portion of the operating voltage to the first core. 
     In an example, the method further comprises, in response to determining that the temperature of the first region exceeds the thermal threshold, accessing a table to identify the second integrated voltage regulator, the table including a plurality of entries each to identify a region of the processor and one or more of the plurality of integrated voltage regulators. 
     In an example, the method further comprises, in response to determining that the temperature of the first region exceeds the temperature threshold, causing the first integrated voltage regulator to be disabled. 
     In an example, the method further comprises, in response to determining that the temperature of the first region exceeds the thermal threshold: sending one or more first gate control signals to a first subset of power gates of the first integrated voltage regulator to cause the first subset of power gates of the first integrated voltage regulator to be disabled; and sending one or more second gate control signals to a second subset of power gates of the first integrated voltage regulator to cause the second subset of power gates of the first integrated voltage regulator to be enabled. 
     In an example, the method further comprises, in response to determining that the temperature of the first region exceeds a second thermal threshold, the second thermal threshold less than the first thermal threshold, reducing a number of active power gates of the first integrated voltage regulator. In another example, a computer readable medium including instructions is to perform the method of any of the above examples. 
     In another example, a computer readable medium including data is to be used by at least one machine to fabricate at least one integrated circuit to perform the method of any one of the above examples. 
     In another example, an apparatus comprises means for performing the method of any one of the above examples. 
     In yet another example, a system comprises: a processor having a plurality of cores and a plurality of low dropout regulators to power the plurality of cores, where a first low dropout regulator of the plurality of low dropout regulators comprises a plurality of power gates, where when a hot spot region is identified within a first core associated with the first low dropout regulator, at least some of the plurality of power gates of the first low dropout regulator are to be disabled; and a system memory coupled to the processor. 
     In an example, when an activity level of a first portion of the first core exceeds a threshold, one or more of the plurality of power gates of the first low dropout regulator located in the first portion of the first core are disabled. 
     In an example, the processor further comprises a fuse storage to store configuration information regarding the plurality of low dropout regulators, the fuse storage to store a plurality of indicators, each to indicate whether a corresponding one of the plurality of low dropout regulators is to be enabled, where the plurality of low dropout regulators are oversubscribed with respect to the plurality of cores. 
     Understand that various combinations of the above examples are possible. 
     Note that the terms “circuit” and “circuitry” are used interchangeably herein. As used herein, these terms and the term “logic” are used to refer to alone or in any combination, analog circuitry, digital circuitry, hard wired circuitry, programmable circuitry, processor circuitry, microcontroller circuitry, hardware logic circuitry, state machine circuitry and/or any other type of physical hardware component. Embodiments may be used in many different types of systems. For example, in one embodiment a communication device can be arranged to perform the various methods and techniques described herein. Of course, the scope of the present invention is not limited to a communication device, and instead other embodiments can be directed to other types of apparatus for processing instructions, or one or more machine readable media including instructions that in response to being executed on a computing device, cause the device to carry out one or more of the methods and techniques described herein. 
     Embodiments may be implemented in code and may be stored on a non-transitory storage medium having stored thereon instructions which can be used to program a system to perform the instructions. Embodiments also may be implemented in data and may be stored on a non-transitory storage medium, which if used by at least one machine, causes the at least one machine to fabricate at least one integrated circuit to perform one or more operations. Still further embodiments may be implemented in a computer readable storage medium including information that, when manufactured into a SoC or other processor, is to configure the SoC or other processor to perform one or more operations. The storage medium may include, but is not limited to, any type of disk including floppy disks, optical disks, solid state drives (SSDs), compact disk read-only memories (CD-ROMs), compact disk rewritables (CD-RWs), and magneto-optical disks, semiconductor devices such as read-only memories (ROMs), random access memories (RAMs) such as dynamic random access memories (DRAMs), static random access memories (SRAMs), erasable programmable read-only memories (EPROMs), flash memories, electrically erasable programmable read-only memories (EEPROMs), magnetic or optical cards, or any other type of media suitable for storing electronic instructions. 
     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.