Abstract:
A computer system and a method of operating a service-processor-centric computer system. In one embodiment, the computer system includes: (1) a CPU configured to issue control signals and (2) a service processor configured for intercepting and handling the control signals, the handling including delaying, modifying or ignoring the control signals, the service processor further configuring for issuing highest-priority control signals.

Description:
TECHNICAL FIELD 
     This application is directed, in general, to computer architectures and, more specifically, to microprocessor-based computer architectures. 
     BACKGROUND 
     From an architectural standpoint, computer systems are centered about a general-purpose central processing unit (CPU), which is responsible for controlling the system and performing at least the bulk of data processing. The rest of the architecture radiates out from the CPU and includes memory and peripherals (e.g., input/output, or I/O, devices). 
     In a microprocessor-based computer system (such as found in a modern desktop, laptop, tablet or Smartphone), the CPU takes the form of a microprocessor having one or more processing cores. The rest of the system typically includes volatile memory (e.g., dynamic random-access memory, or DRAM), a graphics interface, nonvolatile (e.g., flash or read-only) memory, a network interface, one or more disk drives and keyboard, mouse and other interfaces (e.g., via a plurality of ports, such as Universal Serial Bus, or USB, ports). 
     As microprocessor-based computer systems have become more powerful and capable, and as microprocessors have become more complex and energy-consumptive (.e., hotter), it has become desirable to distribute the processing. Accordingly, “chipsets” (a term used in the art to describe one or more integrated circuits that work in tandem with, and as an interface for, a particular type of CPU) and special-purpose processors, such as math co-processors, service processors and graphics processing units (GPUs) are now routinely used to take some of the processing load off the CPU. In such systems, the CPU performs general processing, and the special-purpose processors perform the tasks for which they were specifically designed. Irrespective of the degree or extent to which processing has become more distributed, the CPU still controls the system and remains the center of the architecture. 
     SUMMARY 
     One aspect provides a computer system. In one embodiment, the computer system includes: (1) a CPU configured to issue control signals and (2) a service processor configured for intercepting and handling the control signals, the handling including delaying, modifying or ignoring the control signals, the service processor further configuring for issuing highest-priority control signals. 
     In another embodiment, the computer system includes: (1) a CPU configured to issue control signals, (2) a service processor configured for intercepting and handling the control signals, the handling including delaying, modifying or ignoring the control signals, the service processor further configuring for issuing highest-priority control signals (3) at least one peripheral device coupled to the CPU via the service processor, (4) a network interface coupled to the CPU via the service processor and (5) at least one drive coupled to the CPU via the service processor. 
     Another aspect provides a method of operating a service-processor-centric computer system. In one embodiment, the method includes: (1) initializing the system in a boot state, the initializing comprising booting a service processor of the system and then booting a CPU of the computer system, (2) transitioning the system to a cooperative processing state, (3) further transitioning the system to one of a separate processing state and a service processing state, (4) transitioning the system back to the cooperative processing state and (4) transitioning the system to a shutdown state. 
    
    
     
       BRIEF DESCRIPTION 
       Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram of one embodiment of a service-processor-centric computer architecture; 
         FIG. 2  is a diagram showing different operational modes of one embodiment of a service-processor-centric computer architecture; and 
         FIG. 3  is a state diagram showing states and transitions thereamong illustrating a method of operating one embodiment of a service-processor-centric computer system. 
     
    
    
     DETAILED DESCRIPTION 
     As stated above, CPUs control conventional computer systems. (It should be mentioned as an aside that some ancillary circuits may assume temporary control during startup, shutdown, or under some fault conditions, but the CPU remains the architectural center and predominates during normal operation.) Accordingly, CPUs are deliberately equipped with circuitry to govern bus access, assert highest-priority interrupts and otherwise provide ultimate system control. CPUs also tend to be optimized for single-threaded (non-parallel) processing. 
     It is realized herein, however, that significant advantages may result from a computer architecture that does not have its CPU as its architectural center. (“Center” is used herein to denote importance relative to other system components, reflected in terms of priority and control, and not in terms of physical location on, e.g., a circuit board.) It is also realized herein that an improved architecture may result were a service processor to be made the architectural center and given ultimate system control and the CPU, being a general-purpose device, made subject to the control of the service processor. It is further realized that an architecture that operates with an unmodified CPU may be advantageous in some applications. As will be described hereinafter, such an improved architecture can exhibit significant advantages with respect to speed, power consumption, security and flexibility. For purposes of this disclosure, a CPU is a general-purpose processor, such as a microprocessor, that is designed to exercise top-priority control over a computer system. A service processor, in contrast, has an internal architecture attuned to carrying out more specialized tasks, such as carrying out computationally-intensive mathematics; rendering vector or raster graphics; or encrypting and decrypting data. Because such specialized tasks are well-suited for parallel processing, service processors are often optimized for parallel processing. 
       FIG. 1  is a block diagram of one embodiment of a service-processor-centric computer architecture  100 . A service processor  110  lies at the center of the architecture  100 . The service processor  110  is a special-purpose processor. In the illustrated embodiment, the service processor  110  is optimized for parallel-processing. In one embodiment, the service processor  110  is a unified collection of strong co-processors managed by a lightweight general-purpose unit. As those skilled in the art understand, desktop, laptop, tablet, and even system-on-a-chip (SoC) CPUs have two primary functions: (1) managing a system and (2) producing results on their own. These two primary functions are jointly optimized in the design of a CPU. In contrast, lightweight general-purpose units, while capable of producing results on their own, are primarily focused on management activities. The design of a lightweight general-purpose unit reflects this primary focus. 
     The architecture  100  further includes a CPU  120 . In contrast with the service processor  110 , the CPU  120  is jointly optimized to managing a system and produce results on its own. In the illustrated embodiment, the CPU  120  is optimized for single-threaded (non-parallel) processing. Generally speaking, the CPU  120  is configured to execute tasks faster than the service processor  110 . However, the service processor  110  may be capable of executing certain tasks, namely those for which the service processor  110  was particularly designed, faster than the CPU  120  by executing the tasks through one or more of its strong co-processors. Also generally speaking, the CPU  120  consumes more power than does the service processor  110  in normal operation. In one embodiment, the CPU  120  is a Core™ or Pentium™ processor commercially available from the Intel Corporation of Santa Clara, Calif. However, those skilled in the pertinent art will understand that other general-purpose processors, including those that are not classified as microprocessors, may be employed as the CPU  120 . 
     In the illustrated embodiment, a chipset  130  is coupled to the CPU  120  via a bus  180   a . As described above, the chipset  130  includes at least one integrated circuits external to the CPU  120 , but nonetheless designed to work in tandem with, and as an interface for, the CPU  120 . For this reason, the bus  180   a  is typically a proprietary bus particular to the CPU  120  and the chipset  130 . For example, if the CPU  120  is a Core™ processor, the chipset  130  may be a B75 chipset, also commercially available from the Intel Corporation of Santa Clara, Calif. 
     In the embodiment of  FIG. 1 , a bus  180   b  couples the service processor  110  to the chipset  130 . While the bus  180   b  may be a proprietary bus, it more typically conforms to an industry standard, such as the Peripheral Component Interconnect (PCI) standard. 
     DRAM  140  is coupled to the chipset  130  via a bus  180   c . The DRAM  140  may be of any size, speed or configuration and may include other types of memory, such as read-only or flash memory. The bus  180   c  is typically known as a “system bus.” 
     One or more peripherals  150  are coupled to the service processor  110  via a bus  180   d . The one or more peripherals may include USB devices, such as USB flash drives (UFDs), USB hard drives, keyboards, trackballs, mice, game controllers, cameras and sound cards. Accordingly, the bus  180   d  may include a PCI or other type of expansion bus and one or more USB ports. 
     In the illustrated embodiment, a network interface  160  is coupled to the service processor  110  via a bus  180   e . In various embodiments, the network interface  160  is a wireless (e.g., IEEE 802 interface) or wireline (e.g., Ethernet™ copper or FX fiber interface). The bus  180   e  may include a PCI or other type of expansion bus. 
     One or more drives  170  are shown as being coupled to the service processor  110  via a bus  180   f . The various of the one or more drives  170  may be solid-state or disk-based, may be magnetic, optical or magneto-optic and provide nonvolatile mass storage for data processed by the system  100 . The bus  180  may be of any type, including Integrated Drive Electronics (IDE), enhanced IDE (EIDE), and Advanced Technology Attachment (ATA) of either the serial (SATA) or parallel (PATA) kind. 
     While the architecture of  FIG. 1  so far appears conventional in many ways, it is not. In a conventional architecture, the CPU  120  has the highest priority and is the ultimate authority for the system  100 . Accordingly, the CPU  120  governs the buses  180   a ,  180   b ,  180   c  and controls, either directly or indirectly, the buses  180   d ,  180   e ,  180   f . No other part of a conventional architecture has co-equal or superior control in the course of normal system operation. 
     In contrast, in the architecture of  FIG. 1 , the service processor  110  has the highest priority and is the ultimate authority for the system  100 . The CPU  120 , especially if it is a conventional, commercially-available CPU, issues conventional, top-priority control signals, but they are routed to the service processor  110 , which then determines how to handle the control signals. In some cases, depending upon how the service processor  110  is configured or programmed, the service processor  110  may mimic or repeat the control signals, such that the CPU  120  still appears to be in control of the system. In other cases, again depending upon configuration or programming, the service processor  110  may delay, modify (e.g., change the type or priority of) or altogether ignore (e.g., mask) the control signals the CPU  120  issues. It is important to note that the CPU  120  does not enjoy the same privilege with respect to the control signals the service processor  110  issues; the CPU  120  cannot delay, modify or change the priority of any of the control signals the service processor  110  issues. 
     From an architectural standpoint, the control signals issued by the CPU  120  may be conveyed via the bus  180   a , through the chipset  130  and via the bus  180   b  to the service processor  110 . In an alternative embodiment, a separate bus  180   g  may directly couple the CPU  120  and the service processor  110 , bearing the control signals issued by the CPU  120  and separating the control signals from other control signals. 
     Having described various embodiments of the novel architecture in general, various aspects of its operation will now be described, which will, among other things, shed some light on its potential advantages in certain applications.  FIG. 2  is a diagram showing different operational modes of one embodiment of a service-processor-centric computer architecture. In  FIG. 2 , the architecture is represented in three columns. The middle column represents the service processor ( 110  of  FIG. 1 ). The right-hand column represents the CPU ( 120  of  FIG. 1 ). The left-hand column represents at least some of the rest of the architecture (including, e.g., the peripherals  150 , the network interface  160 , the drives  170 , and perhaps even the DRAM  140 ). 
     The illustrated embodiment of the architecture of  FIG. 1  is configured to operate in three general modes: a “cooperative processing” mode, a service processing mode and a “separate processing” mode. The cooperative processing and separate processing modes may be considered “high-power” modes relative to the service processing mode. Of course, “high-power” and “low-power” are relative terms and not necessarily accurate in all instances. 
     In the cooperative processing mode, the CPU performs primary processing  230  for the system, the service processor provides service processing  220  (e.g., math, graphics or other function-specific processing) for the CPU, and the rest of the architecture provides an I/O support role  210 , as  FIG. 2  shows. The service processing may include the provision of “filters” for the benefit of the CPU. As those skilled in the pertinent art are aware, filters are ancillary programs that process and often modify streams of data. Filters include encryption/decryption filters, protocol stack filters, hardware abstraction filters, device handlers and network masks and address mapping filters. 
     Arrowheaded lines spanning the CPU, the service processor and the rest of the architecture signify that substantial control, address and data communication and processing are occurring thereamong. It should be borne in mind that, while the service processor only provides service processing for the CPU, the service processor is in control of the overall system, handling CPU control signals as described above. 
     In the service processing mode, the service processor performs the primary processing  250  for the system, and the rest of the architecture provides the I/O support role  240 . The CPU is idle (e.g., in a sleep mode) or turned off  260 . In the service processing mode, the service processor functions as the de facto CPU for the system. While an arrowheaded line spans the service processor and the rest of the architecture,  FIG. 2  omits an arrowheaded line spanning the service processor and the CPU to signify that the CPU is idle or turned off  260  in the service processing mode and thus unavailable for substantial control, address or data communication or processing. 
     In the separate processing mode, the service processor performs the primary processing  280  for the system, and the rest of the architecture provides the I/ 0  support role  270 . However, unlike the service processing mode, the CPU is active, and not idle. In the separating mode, the architecture essentially splits into two separate systems. One system includes the service processor and the rest of the architecture, and the other system includes the CPU (and also the chipset  130  and DRAM  140  of  FIG. 1  in some embodiments. In the separate processing mode (as with the service processing mode), the service processor functions as the de facto CPU for the system that includes the service processor. The CPU functions as the CPU for the system that includes the CPU and is typically involved in background processing  290  of some sort. As with the service processing mode,  FIG. 2  omits an arrowheaded line spanning the service processor and the CPU to signify that insubstantial control, address or data communication or processing occurs between the service processor and the CPU in the separate processing mode. 
     In general, the three above-described modes may be employed to advantage as follows. (1) The cooperative processing mode is advantageous for normal system operation, particularly involving substantial user interaction and intensive data processing. (2) The service processing mode is advantageous for relatively low-power operation, particularly involving only intermittent user interaction or light data processing. (3) The separate processing mode is advantageous for allowing the relatively light data processing of the service processing mode while carrying out substantial data processing activity in the background (e.g., operating system or application software installation or updating or operating system rebooting). 
       FIG. 3  is a state diagram showing states and transitions thereamong illustrating a method of operating one embodiment of a service-processor-centric computer system.  FIG. 3  is presented primarily for the purpose of showing how the architecture of  FIG. 1  may be initialized, shut down or transitioned among the various modes described in conjunction with  FIG. 2 . 
     In a boot state  310 , a system incorporating an embodiment of the architecture of  FIG. 1  is initialized. Because the service processor is at its architectural center, the service processor is booted first, followed by the CPU. This is opposite a typical conventional system boot order. 
     Once the system has completed initialization, it transitions out of the boot state into a cooperative processing state  320 . In the cooperative processing state  320 , the CPU performs primary processing, and the service processor provides service processing and controls the system. 
     The illustrated embodiment of the system can then transition, either programmatically or in response to an explicit user command, to a separate processing state  330 . In the separate processing state  330 , the CPU performs primary (background) processing for its separate system, and the service processor provides primary processing for its separate system. The system can then transition, either programmatically or in response to an explicit user command, back to the cooperative processing state  320 . 
     The illustrated embodiment of the system can alternatively transition, either programmatically or in response to an explicit user command, to a service processing state  340 . In the service processing state  340 , the service processor provides primary processing for the separate system, and the CPU is idle or turned off. The system can then transition, either programmatically or in response to an explicit user command, back to the cooperative processing state  320 . 
     The illustrated embodiment of the system can also transition, either programmatically or in response an explicit user command, from the separate processing state  330  to the service processing state  340 . The system can then transition, either programmatically or in response to an explicit user command, back to the cooperative processing state  320 . 
     The illustrated embodiment of the system can then transition to a shutdown state  350  from either the cooperative processing state  320  or the service processing state  340 , either programmatically or in response to an explicit user command. In an alternative embodiment, the system can also transition to the shutdown state  350  from the separate processing state  330 . However, care should be taken not to corrupt data being processed by the CPU in the background in making such transition. 
     Having described modes of operation and transitions thereamong, some applications that would find advantageous use of the architecture disclosed herein will now be described. 
     Gaming: Gaming is widely regarded as a difficult activity for a computer system to undertake. It usually requires substantial user interaction and intensive data processing and usually features the rendering of complex graphics. Gaming is a good candidate for the cooperative processing mode, in which a graphics-oriented service processor can, in the context of the architecture of  FIG. 1 , not only function as a GPU to render the graphics, but also handle I/O with the peripherals and the drives. This frees the CPU to handle the bulk of the processing associated with gameplay. Unlike a conventional architecture, the novel architecture disclosed herein can carry out the graphics and I/O functions in the service processor and not burden the CPU with the “overhead” of controlling those functions. 
     Drive security: Nonvolatile storage security is of particular concern in portable computer systems, such as those taken on trips by so-called “road warriors.” The data on the drives may be disclosed if the computer is lost or stolen. To address this this issue, encryption has begun to be used to increase the security of the data stored on the drives. Unfortunately, in a conventional architecture, the CPU suffers the burden of encrypting and decrypting the data communicated with the drives. In the cooperative processing mode, the service processor can perform encryption and decryption with respect to the data transferred to and from the drives, perhaps in the context of a virtual private network (VPN) established between the service processor and the drives. Like the gaming application described above, the CPU is not burdened with controlling either the encryption or the decryption and is therefore free to perform other functions. 
     Business server: Servers commonly used by businesses perform many “housekeeping” or background tasks that are not directly related to the serving of files, printers or network resources. In the cooperative processing mode, the service processor can perform housekeeping or background tasks such as anti-virus scanning, terminal services display compression and firewall packet “sniffing.” Like the gaming and drive security applications described above, the CPU is not burdened with controlling the carrying out of this task and therefore left to perform other functions. 
     Home desktop computer: Home computers are often used sporadically. Conventional architectures provide a sleep mode in which the CPU is idled or turned off to save power. Unfortunately, time is required to transition a computer out of sleep mode, perhaps frustrating its user. In contrast to conventional architectures, the architecture disclosed herein leaves the service processor active in the service processor mode, meaning that relatively light processing is available on demand. Thus, the home computer can function as an “instant-on” Internet appliance or media player, perhaps while transitioning to the cooperative processing mode for more substantial processing, such as may be needed for gaming or finance. The drive security function described above can also be incorporated, allowing each user to have his own virtual, secure drive. 
     Laptop computer: Like the home desktop computer application described above, the architecture disclosed herein allows a laptop computer to function in the service processing mode as an instant-on Internet appliance or media player. The service processor can undertake these or other relatively light-processing tasks without engaging the CPU, potentially resulting in significantly lower power usage. In some embodiments, the system can transition to the service processing mode without the user being aware of it. 
     Other applications: The architecture disclosed herein may have one or more of the following abilities or advantages, depending upon the manner in which it is embodied in a particular system. In the separate processing mode, a user can browse the Internet or play media (using the service processor) while the CPU is installing or updating the operating system. In the cooperative processing mode or service processing mode, the service processor can mirror the drives or otherwise back up data. In the cooperative processing mode, the service processor can act as a controller for drives arranged in a redundant array of independent disks (RAID) without requiring an application-specific integrated circuit (ASIC) dedicated to RAID. Likewise, in the cooperative processing mode, the service processor can act as a VPN controller without requiring a network interface card (NIC) ASIC. In the separate processing mode or the service processing mode, the service processor can cooperate with network-based processing resources to implement a kernel-based virtual machine (KVM) without requiring processing by the CPU. The service processor can also perform remote power and reset control functions via the network. In the cooperative processing mode, the CPU can cooperate with network-based processing resources to implement a KVM, while the service processor supports the KVM with functions such as video compression. 
     The specialized functions performed by the service processor can also be updated via software or firmware without burdening the CPU. This is in contrast to conventional architectures that use non-upgradeable ASICs or burden the CPU with software or firmware updates. The service processor can act as a virtual machine manager (VMM), or “hypervisor,” to the peripherals, network or drives, allowing the peripherals, network or drives to be “virtualized” to support multiple operating systems with high security. 
     In some embodiments, the cooperative processing mode could be employed to allow an operating system to configure tasks for processing by the service processor. The service processing mode can then be entered, in which the CPU is idled or turned off, and the service processor processes the tasks that were set up in the cooperative processing mode. 
     In some embodiments, custom background applications, such as web browsers and media players, can use the service processor while the CPU is idle or turned off. In other embodiments, devices such as network-attached storage (NAS) and digital video disc (DVD) drives may be able to be controlled remotely without the CPU&#39;s involvement. In general, the service processor is able to perform background, housekeeping and driver tasks for the CPU without requiring the CPU&#39;s control or intervention, leaving the CPU free for more general processing. 
     Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments.