Abstract:
Embodiments of the present invention relate to a system and method for providing processing capacity on demand. According to the embodiments, a processor package has a plurality of processing elements. One or more of the processing elements may be made active in response to increased demand for processing capacity based on modifiable authorization information.

Description:
BACKGROUND  
       [0001]     The term “capacity on demand” as it relates to computer systems refers generally to adding resources on an as-needed basis. In particular, processing capacity could be added on demand.  
         [0002]     Known arrangements for adding processing capacity on demand involve providing latent processing capacity that is unused until a need for extra capacity arises. When a need arises, the latent processing capacity may be tapped, and then allowed to again become unused when the need passes. For example, latent processing capacity could be added to a high-end server in a data network such as the Internet, and called upon only during periods of peak traffic. Letting the processing capacity be unused until needed reduces costs, since agreements may be made with capacity providers that only capacity that is actually used will be paid for.  
         [0003]     In some known arrangements, latent or reserve processing capacity may be provided in processor packages that are added to a system&#39;s hardware platform. The processor packages may be brought into use at a platform level, in a manner analogous to using a relay to connect power to a circuit to bring the circuit into use. When reserve capacity is used in this way, it involves adding the capacity in bulk form, that is, in units of one or more entire processor packages. Finer granularity is not possible, in that individual processing elements on a processor package cannot be selectively brought into use. Such an approach may be wasteful if all processing elements on a processor package are not needed.  
         [0004]     Other known arrangements may be able to selectively activate individual processing elements on a processor package for added capacity. Such arrangements may use a form of power management to regulate how many processing elements are active. In this power management approach, processing elements not in use may be placed into a low power state to conserve energy, and then placed into a higher power state when put into use. Additionally, known power management techniques typically require that managed devices be made continuously “visible” (in an understood operating system software sense) to associated BIOS (Basic Input/Output System) and operating system software. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  shows a processor package according to embodiments of the present invention;  
         [0006]      FIGS. 2-4 ,  4 A and  5  show process flows according to embodiments of the present invention; and  
         [0007]      FIG. 6  shows a system according to embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0008]     One embodiment of the present invention relates to performing a process to check authorization information corresponding to available reserve processing capacity to determine if the reserve processing capacity is authorized for use, and if the authorization information indicates that the reserve processing capacity is authorized for use, using the reserve processing capacity. The check may be inserted in a non-intrusive way into standard firmware initialization routines, making implementation comparatively inexpensive. Moreover, the reserve processing capacity need not be made continuously visible to an operating system, reducing security concerns.  
         [0009]     In embodiments, the reserve processing capacity may be processing elements on a processor package, and the authorization information may be contained in a data storage area on the processor package. The data storage area could be, for example, a register to store an authorization status for each processing element. Based on a respective status for each processing element, the processing elements may be brought into use selectively and individually.  
         [0010]      FIG. 1  shows an example of a processor package  100  according to embodiments of the present invention. The processor package  100  may comprise a plurality of processing elements  101 . One or more of the processing elements  101  may be reserve processing elements  101 . 1  that are not used unless there is a demand for increased capacity, while others of the processing elements may be regularly-used processing elements  101 . 2 . As is typical for many known processor packages, the processor package  100  may further include a cache  102  and a region  103  distinct from the processing elements containing, for example, bus interface logic. According to embodiments of the present invention, the region  103  may further include a storage area for authorization information  104 . The storage area  104  could be implemented, for example, as a register having a bit corresponding to each processing element. A status of each bit could indicate whether a corresponding processing element was authorized for use. For example, a bit with a logic value of “1” could indicate that a corresponding processing element was authorized for use, while a bit with a logic value of “0” could indicate that a corresponding processing element was not authorized for use. Based on the authorization information in the register  104 , reserve processing elements may be activated for use on demand to add to the processing capacity provided by the regular-use processing elements.  
         [0011]     The authorization information could be set by any of a number of secure mechanisms. For example, many high-end server platforms include a service controller that can be coupled to platform components and used to program the components. Such a service controller could, for example, be used by an authorized person to set bits in the register  104  to activate one or more of the reserve processing elements during a period of increased demand. Or, for example, the bits could be automatically set by secure software based on certain triggering events, such as a demand threshold being met or exceeded.  
         [0012]     A processor package  100  shipped by a vendor to a user could have a set of regular processing elements that would ordinarily be active, and a set of reserve processing elements that would be inactive unless called on by increased demand for processing capacity. There could be an agreement between the vendor and the user wherein, for example, the user could selectively activate reserve processing elements and make a corresponding per-use payment to the vendor. In one embodiment, the processing elements are processor cores and the processor is a multi-core processor.  
         [0013]      FIG. 2  shows a process flow according to embodiments of the present invention for adding reserve processing elements to the processing capacity of a processor package  100 . As shown in block  200 , the processor package could be placed into use with the regular processing elements active and the reserve processing elements initially inactive.  
         [0014]     Then, a need for increased processing capacity could arise in the user&#39;s system. For example, the processor package could have been placed into use in a server system in a data network that began to experience increased traffic. Accordingly, the system could receive a request for additional processing capacity, as shown in block  201 .  
         [0015]     Based on the request for additional capacity, the authorization information for the inactive processing elements could be updated, as shown in block  202 . This could be performed by a secure operation as described above. The secure operation could cause one or more bits in a register  104  of the processing package to be set to the appropriate logic value.  
         [0016]     One or more of the previously inactive processing elements could then be signaled to become active, as shown in block  203 . If signaled to become active, a previously inactive processing element may check the authorization information to determine if it is authorized to become active, as shown in block  204 . If authorized to become active, the previously inactive processing element may become active, as shown in block  205 . Becoming active may involve executing initialization processes, including known BIOS (Basic I/O System) routines, to become ready to come “online” for use. When the previously inactive processing element is ready to come online, an operating system of whatever hardware platform the previously inactive processing element is installed on may be notified of the availability of the previously inactive processing element and begin to use it.  
         [0017]     Operations associated with reaching the state illustrated by block  200 , above, may involve initialization operations. One such initialization operation is sometimes termed a “cold reset” and involves an initial power-up of a hardware device. In known systems, following a cold reset, a plurality of processing elements on a processor package may elect a single bootstrap processing element by a known election process. The bootstrap processing element is responsible for executing bootstrap routines and bringing the non-bootstrap processing elements online.  FIG. 3  shows a process associated with a cold reset according to embodiments of the present invention. Following a cold reset as shown in block  300 , a plurality of processing elements may elect a bootstrap processing element as shown in block  301 .  
         [0018]     The non-elected processing elements may enter an inactive state, as shown in block  302 . Known processing systems may include firmware to create such an inactive state. The firmware, for example, may be stored in read-only memory (ROM) and be specific to a particular processor architecture. The firmware may also be referred to as “micro-code” or “micro-instructions” and may be contained on the processor in hard coded or other format in some embodiments. In some embodiments, the inactive state may be a “Wait_for_SIPI” (Wait_for_Startup Inter-Processor Interrupt) state as known in Intel® x86 processor architecture. As shown in block  303 , as part of the execution of firmware according to embodiments of the present invention pursuant to a cold reset, the bootstrap processing element may then read authorization information in register  104 . The firmware could be, for example, firmware of the Intel® x86 processor architecture. If the authorization information indicates that the bootstrap processor is authorized for use, the bootstrap processing element may proceed with the rest of its initialization, as shown in block  304 . Otherwise, the bootstrap processor may enter an inactive state along with the rest of the processing elements. In the latter situation, the entire processor package would be inactive.  
         [0019]     More typically, however, there may be a set of processing elements authorized for regular use in the authorization information. After the bootstrap processing element of this regular-use set was initialized, the bootstrap processing element might begin to bring others of the regular-use processing elements into use. A process for this according to embodiments of the present invention is shown in  FIG. 4 . As shown in block  400 , processing element k of N total processing elements on a processor package may be inactive. In embodiments, this inactive state may be a Wait_for_SIPI state that may have been entered following a cold reset, as illustrated by the flow of blocks  300 - 302  (see  FIG. 3 ) discussed above.  
         [0020]     The bootstrap processing element might then issue a signal  404  to processing element k to cause it to leave the inactive state. In embodiments, the signal  404  may be a “Startup Inter-Processor Interrupt” (SIPI) of the known Intel® x86 processor architecture. A SIPI signal may cause a processing element in the Wait_for_SIPI state to leave or “wake up” from the Wait_for_SIPI state. The SIPI could cause processing element k to leave the inactive state and check the authorization information, as shown in block  401 . If authorized, processing element k may proceed to complete its initialization, as shown in block  403 . Otherwise, processing element k may return to an inactive state, as shown in block  402 .  
         [0021]     Following a cold reset, the process of  FIG. 4  could be performed for each of the N processing elements. The authorization information would determine which of the N processing elements was brought into use. As noted earlier, there could be a regular-use set of processing elements designated in the authorization information, and a set of reserve processing elements designated in the authorization information.  
         [0022]     According to embodiments of the present invention, a check of the authorization information as represented by block  303  ( FIG. 3 ) and block  401  ( FIG. 4 ) may also be performed pursuant to a “warm reset” (e.g., a reset such as that caused by assertion of an INIT pin on an Intel® x86 processor) as opposed to a cold reset (e.g., assertion of a RESET pin) as in  FIG. 3 . In a warm reset, there may be no initial powering-up of hardware. A process according to embodiments of the present invention corresponding to a warm reset is shown in  FIG. 4A . Following a warm reset of a processing element as shown in block  450 , as part of the execution of firmware according to embodiments of the present invention pursuant to a warm reset, the processing element may read the authorization information, as shown in block  451 . The firmware could be, for example, firmware of the Intel® x86 processor architecture. If authorized, the processing element may proceed to complete its initialization, as shown in block  453 . Otherwise, the processing element may enter an inactive state, as shown in block  452 .  
         [0023]     Following execution of the processes of  FIGS. 3 and 4 , a system including a processor package according to embodiments of the present invention may reach the state shown in block  200  of  FIG. 2 . The process of  FIG. 4  may be further used to implement other operations shown in  FIG. 2 . More specifically, after a request for additional processing capacity (block  201 ,  FIG. 2 ) and a corresponding update of the authorization information (block  202 ,  FIG. 2 ) to authorize one or more of the reserve processing elements for use, a signal to become active (e.g., a SIPI) may be issued to a previously inactive processing element (e.g., a processing element in a Wait_for_SIPI state) as shown in block  400  and signal  404  ( FIG. 4 ). The previously inactive processing element may then check the authorization information to determine if it is authorized to become active as shown in corresponding blocks  401  ( FIG. 4 ) and  204  ( FIG. 2 ). If it is authorized, the previously inactive processing element may become active, as shown in corresponding blocks  403  ( FIG. 4 ) and  205  ( FIG. 2 ).  
         [0024]     It should be understood that a processing element need not enter an inactive state only following a cold reset. A processing element could be placed into an inactive state after a period of activity, by causing the associated operating system and BIOS to no longer recognize the processing element as active or available. This could include placing the processing element in a Wait_for_SIPI state. Then, the authorization information could be correspondingly updated. Then, the processing element could be again made active, and again inactive, based on demand. Such a process is illustrated generally in  FIG. 5 .  FIG. 5  shows operations that could occur on an “up-and-running” system as variations in the level of demand for processing capacity were experienced, and the authorization information was correspondingly modified. As shown in block  500 , a first distribution of processing elements in a processor package may be defined in the authorization information, where the first distribution defines a set of processing elements authorized to be active and a set of processing elements not authorized to be active. As shown in block  501 , the set of processing elements authorized to be active according to the first distribution may be used, while the unauthorized set remains inactive.  
         [0025]     As shown in block  502 , based on a change in demand for processing capacity, the authorization information may be modified to define a second distribution of the processing elements different from the first distribution. The second distribution may define more processing elements authorized to be active than does the first distribution. On the other hand, the second distribution may define fewer processing elements authorized to be active than does the first distribution. Pursuant to the modification of the authorization information, the authorization information may be checked by respective processing elements to determine their authorization statuses, as shown in block  503 . Based on their respective authorization statuses, one or more processing elements may become active, or become inactive, as shown in block  504 . As a result, the system may be used with the second distribution of processing elements, as shown in block  505 .  
         [0026]     As noted earlier, embodiments of the present invention may realize economies of implementation in that straightforward checks for authorization may be inserted in standard system firmware as described above. Other standard software also meshes well with operations according to embodiments of the invention. For example, block  203  ( FIG. 2 ) could be preceded by standard firmware operations (not illustrated) associated with detecting a device newly added to system hardware and making the device recognized to an operating system. An example of a suitable firmware process of this kind is known in some systems as a “Processor Online Flow.” A Processor Online Flow could include or culminate in a signal to a previously inactive reserve processing element to become active as shown in block  203 . Along similar lines, “becoming active” as shown in block  205  could include notifying an operating system of the presence of a newly initialized processing element and bringing it online via industry standard ACPI (Advanced Configuration and Power Interface; Version 2.0c, Aug. 25, 2003 by Intel Corp. et al.) operations for interfacing between a BIOS (Basic Input/Output System) and an operating system.  
         [0027]      FIG. 6  is a block diagram of a computer system, which may include an architectural state, including one or more processor packages and memory for use in accordance with an embodiment of the present invention. In  FIG. 6 , a computer system  600  may include one or more processor packages  610 ( 1 )- 610 ( n ) coupled to a processor bus  620 , which may be coupled to a system logic  630 . Each of the one or more processor packages  610 ( 1 )- 610 ( n ) may be N-bit processor packages and may include a decoder (not shown) and one or more N-bit registers (not shown). System logic  630  may be coupled to a system memory  640  through a bus  650  and coupled to a non-volatile memory  670  and one or more peripheral devices  680 ( 1 )- 680 ( m ) through a peripheral bus  660 . Peripheral bus  660  may represent, for example, one or more Peripheral Component Interconnect (PCI) buses, PCI Special Interest Group (SIG) PCI Local Bus Specification, Revision 2.2., published Dec. 18, 1998; industry standard architecture (ISA) buses; Extended ISA (EISA) buses, BCPR Services Inc. EISA Specification, Version 3.12, 1992, published 1992; universal serial bus (USB), USB Specification, Version 1.1, published Sep. 23, 1998; and comparable peripheral buses. Non-volatile memory  670  may be a static memory device such as a read only memory (ROM) or a flash memory. Peripheral devices  680 ( 1 )- 680 ( m ) may include, for example, a keyboard; a mouse or other pointing devices; mass storage devices such as hard disk drives, compact disc (CD) drives, optical disks, and digital video disc (DVD) drives; displays and the like.  
         [0028]     Further, as noted earlier, micro-code for executing processes according to embodiments of the present invention could be stored on a machine-readable medium such as ROM. The micro-code could also be stored on readily portable machine-readable media such as magnetic tape, diskette, CD-ROM and the like.  
         [0029]     Several embodiments of the present invention are specifically illustrated and/or described herein. However, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.