Patent Publication Number: US-9886409-B2

Title: System and method for configuring a channel

Description:
CLAIM OF PRIORITY 
     This application is a divisional of U.S. application Ser. No. 13/902,701 titled “System and Method For Configuring a Channel,” filed May 24, 2013, the entire contents of which is incorporated herein by reference. 
    
    
     This invention was made with Government support under LLNS subcontract B599861 awarded by DOE. The Government has certain rights in this invention. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to channels used in data communications. 
     BACKGROUND 
     Over time, the function of some system components of a computing system has been integrated into the processor chip. Today, such functions include that of memory controllers, network interface controllers, and general-purpose I/O interfaces. For example, conventional high-end graphics processing units now include as many as six memory controllers along with a Peripheral Component Interconnect Express (PCIe) controller. When the memory controllers are integrated into the processor chip, many hundreds of off-chip pins are needed to connect the memory controllers to external memory devices, such as dynamic random access memory (DRAM). Even when the number of off-chip pins for an interface is reduced, the number of off-chip pins continues to increase as more system components are integrated into the processor chip. For example, when a network interface controller is integrated into a processor chip, off-chip pins needed to couple the network interface controller to a router are added to the processor chip and the off-chip pins that provided the PCIe interface to the network interface controller are retained to enable communication between the processor and other system components. 
     Thus, there is a need for improved utilization of off-chip pins and/or addressing other issues associated with the prior art. 
     SUMMARY 
     An integrated circuit device comprises pin resources, a memory controller circuit, a network interface controller circuit, and transmitter circuitry. The pin resources comprise pads coupled to off-chip pins of the integrated circuit device. The memory controller circuit comprises a first interface and the network interface controller circuit comprises a second interface. The transmitter circuitry is configurable to selectively couple either a first signal of the first interface or a second signal of the second interface to a first pad of the pin resources based on a pin distribution between the first interface and the second interface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a flowchart of a method for configuring a plurality of pin resources, in accordance with one embodiment; 
         FIG. 2A  illustrates a diagram of a system including a processor device with pin resources that provide a channel configuration, in accordance with one embodiment; 
         FIG. 2B  illustrates a diagram of another system including a processor device with pin resources that provide a channel configuration, in accordance with one embodiment; 
         FIG. 3A  illustrates a pin resource that is coupled to transmitter and receiver circuits for two different interfaces, in accordance with one embodiment; 
         FIG. 3B  illustrates a pin resource that is coupled to shared transmitter and receiver circuits for two different interfaces, in accordance with one embodiment; 
         FIG. 4A  illustrates a diagram of another system including a processor device with pin resources that provide a channel configuration, in accordance with one embodiment; 
         FIG. 4B  illustrates a flowchart of a method for dynamically configuring communication channels between a processor device and multiple other devices using a set of off-chip pin resources, in accordance with one embodiment; 
         FIG. 5A  illustrates a diagram of a processor chip with off-chip pins that provide a first channel configuration using generic input/output links, in accordance with one embodiment; 
         FIG. 5B  illustrates a diagram of a system including a multi-processor device with sets of pin resources that provide a channel configuration using generic I/O links, in accordance with one embodiment; and 
         FIG. 6  illustrates an exemplary system in which the various architecture and/or functionality of the various previous embodiments may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     Conventional application specific integrated circuit (ASIC) devices include off-chip pins that are specific to particular input/output (I/O) interfaces. For example, the pins connected to a memory controller and the pins connected to an I/O interface such as PCIe are distinct, meaning that the number of pins (and hence the bandwidth to memory and I/O) is determined at design time and cannot be changed after the chip is fabricated. Oftentimes, different system configurations require different interface configurations. For example, a variety of system configurations may be defined that have different ratios of memory, network, non-volatile storage, and general-purpose I/O bandwidth, depending on the applications to be run on the particular system. Unfortunately, when the number of pins needed for each interface varies between the different systems, a different die is fabricated to produce a device having the particular pin configuration needed for each system. 
     In accordance with one possible embodiment, instead of implementing an ASIC device with pins that are distinct for each interface, the pins may be implemented in a configurable manner, so that one design may be fabricated for different systems. The pins may be configured to serve as connections to memory, connections to the network, or connections to other I/O to match the demands of the system in which the device is used. The pins may be configured for the different systems based on the bandwidth requirements of each of the different interfaces. Further, in one embodiment, the pins in a given system may be reconfigured in the field, to adapt to varying ratios of the interface bandwidths for different applications. 
       FIG. 1  illustrates a flowchart  100  of a method for configuring a plurality of pin resources, in accordance with one embodiment. At operation  105 , a plurality of pin resources of a primary ASIC device is identified. At step  110 , a pin distribution between a first interface and a second interface is obtained, where the first interface provides a first communication path between the primary ASIC device and a first device, and the second interface provides a second communication path between the primary ASIC device and a second device. 
     At step  120 , the pin resources are configured based on the pin distribution. The off-chip pins in the plurality of pin resources may be configured to provide a communication channel between either the primary ASIC device and the first device or the primary ASIC device and the second device. One or more additional sets of pin resources may be configured to provide additional communication channels, as needed, based on the pin distribution. 
     In one embodiment, the pin distribution may be replaced with a bandwidth distribution that is a ratio or a percentage distribution between a memory interface and a network interface. The bandwidth may be measured in bits/second or some other unit of data transfer over time or a width of a bus over a clock rate at which the bus is operated. 
     More illustrative information will now be set forth regarding various optional architectures and features with which the foregoing framework may or may not be implemented, per the desires of the user. It should be strongly noted that the following information is set forth for illustrative purposes and should not be construed as limiting in any manner. Any of the following features may be optionally incorporated with or without the exclusion of other features described. 
     A device may include one or more sets of pins that can be deployed to provide either a communication channel for a storage system, such as memory, or a communication for off-chip I/O, such as a network link. For systems in which the electrical specifications of the storage and I/O interfaces are the same, the pin drivers and receivers on the ASIC device can be shared. If the electrical interfaces are different, the ASIC device may include electrically reconfigurable transmitter and receiver circuits. Alternatively, the transmitter and receiver circuits within the ASIC device may be replicated and connected to the external pad via multiplexing circuits. The pad is a pin resource that is coupled to the physical pin that interfaces between a wire of an integrated circuit and an external wire of a system substrate to which the integrated circuit and one or more other integrated circuits are coupled. For example, a pin may be included as part of a package housing the fabricated die for an ASIC device via a wire bond or ball bump. Alternatively, a pin may be implemented as a through silicon via (TSV) when the device is a die that is included as part of a chip stack. 
     When the number of pins for a device is large, the size of the fabricated die may be determined by the area occupied by the pads which are typically positioned around the die perimeter in a pad ring rather than by the circuitry implemented within the pad ring. Therefore, some conventional ASIC devices include pads for multiple interfaces and only couple (“bond out”) a subset of the pads to pins to manufacture different variations of the ASIC device for different systems. For example, pads may be fabricated in a conventional ASIC device for a 128-bit memory interface to provide a single ASIC device for multiple system configurations. A low-end system configuration may only “bond out” 32 bits of the memory interface while all 128 bits are “bonded out” for a high-end system configuration. Drawbacks of including extra pads in the ASIC device is that the size of the die and resulting cost increases due to the area consumed by the extra pads that are not always needed. Also, the pads are dedicated to a particular interface and cannot necessarily be redeployed for use by another interface. 
     In the context of the present description a configurable channel refers to a communication channel between two devices that is provided by configurable pin resources. In some optional embodiments, the configurable channels may or may not enable high-performance fixed internal logic, such as circuitry that embodies a memory controller or a network interface controller, to be connected flexibly to external devices. Further, in other embodiments, the configurable channels may enable a single ASIC chip to fulfill two different system requirements by repurposing the pins of the ASIC chip and may or may not require the overhead in terms of programmable circuitry that is needed to provide a fully-reconfigurable architecture, such as an field-programmable gate array (FPGA). The pin resources for the configurable channels may or may not only be configurable to support a small set of different I/O standards and it may or may not be necessary for all of the signal pins of the ASIC chip to be configurable. 
       FIG. 2A  illustrates a diagram of a system  200  including a processor device  220  with pin resources that provide a channel configuration, in accordance with one embodiment. Each plurality of pin resources  215  represents a bundle of pads that are coupled to pins dedicated to a particular channel coupling an interface of the processor device  220  to an interface of another device. The processor device  220  is an ASIC device that includes a network interface controller (NIC)  205  and one or more memory controllers  210 . The network interface controller  205  and the memory controllers  210  are circuits that are designed to perform particular functions and may be implemented using custom circuits or standard cells. Once the integrated circuits of the processor device  220  are fabricated to produce a die, the circuitry that embodies a memory controller  210  cannot be modified to convert the circuitry into a network interface controller  205 . In another embodiment, a processor device may include one or more memory controllers  210  and multiple NICs  205 . 
     Each plurality of pin resources  215  may be configured to provide a communication channel for either the network interface controller  205  or the memory controller  210 . As shown in  FIG. 2A , the sets of pin resources  215 -A and  215 -B are coupled to the network interface controller  205  to provide two configurable channels between the network interface controller  205  and a router device  225 . The sets of pin resources  215 -C and  215 -D are each coupled to two of three controllers  210  in a storage system to provide a configurable channel between the memory controller  210 -B and a memory device  230 -B, and the memory controller  210 -C and a memory device  230 -A. In the system  200 , the extra memory controller  210 -A is disabled and may be gated off from a power supply and/or clock. The memory devices  230  may be implemented as DRAM devices, non-volatile memory, storage devices, or any other memory, for that matter. In one embodiment, one or more of the memory devices  230  or the network interface controller  205  may be replaced with an I/O device such as a sensor. 
     The processor device  220  may be fabricated and then configured differently for use in different systems when each system is manufactured. As shown in  FIG. 2A , the pin distribution between memory interfaces and network interfaces is equal. Each plurality of pin resources  215  can be selectively coupled to one of the network interface controller  205  or a memory controller  210 , to provide one or more communication channels between the router device  225  and/or the memory devices  230 , respectively. Therefore, the plurality of pin resources  215  may be configured based on a distribution of pins to provide a desired memory bandwidth and network bandwidth. To enable a variable amount of memory bandwidth, extra memory controllers  210  may be included in the processor device  220  that are enabled when respective sets of pins resources  215  are allocated to the storage system. Alternatively, the width of the memory interface can vary by allocating one or more sets of pin resources  215  to each memory controller  210 , so that a memory controller may operate an interface (i.e., memory bus) at variable width, for example at 32, 64, or 96 bits. The network interface controller  210  can manage variations in available sets of pin resources  215  by adjusting the network channel widths or the number of network slices connected to the router device  225 . While enabling variable amounts of bandwidth requires over-provisioning the circuitry of the processor device  220  by including extra memory controllers  210  and network controllers  205 , unused circuitry can be power-gated to eliminate static and dynamic power draw when the circuitry is not used. 
       FIG. 2B  illustrates a system  250  including a processor device  220  with pin resources that provide a different channel configuration than the system  200 , in accordance with one embodiment. As shown in  FIG. 2B , the pin distribution between memory interfaces and network interfaces is a 3:1 ratio. One of two interfaces on the network interface controller  205  is disabled and the memory controller  210 -A is coupled to a memory device  230 -C. In the system  250 , the router device  270  may be smaller and simpler compared with the router device  225  because the router device  270  has fewer connections to the processor device  220 . Alternatively, the system  250  may employ the same router device as the system  200 , but adjust which processors are connected to which slices of each router, or the system may use the same router devices in the same configuration, but reduce the number of parallel network slices. 
     As shown in  FIG. 2B , the plurality of pin resources  215 -A is coupled to the network interface controller  205  to provide configurable channels between the network interface controller  205  and the router device  270 . The sets of pin resources  215 -B,  215 -C, and  215 -D are each coupled to the three memory controllers  210  in the storage system to provide a configurable channel between the memory controller  210 -A and a memory device  230 -C, the memory controller  210 -B and a memory device  230 -B, and the memory controller  210 -C and a memory device  230 -A. 
     While the systems  200  and  250  have network and memory channel widths that are the same, i.e., the number of pins in each plurality of pin resources  215  equals the width of each interface of a memory controller  210  and a network interface controller  205 , the configurable channels-approach allows for different channel widths. For example, if the memory channel width is wider than the network channel width, one memory channel can be exchanged for multiple network channels. In other words, a single plurality of pin resources  215  may be configured to provide a single memory channel or multiple network channels. 
     Dynamic reconfiguration where pins are redeployed between memory and network by reconfiguring a plurality of pin resources  215  when the system  200  or  250  is in the field is also possible. However, dynamic reconfiguration requires over-provisioning of memory and network resources outside of the processor device  220  to accommodate the maximum potential bandwidth of either subsystem. 
     To allow dynamic reconfiguration or coupling of different controllers to different sets of pin resources  215  after the die containing the integrated circuits of the processor device  220  is fabricated and packaged, the sets of pin resources  215  are designed to selectively connect a set of pads to a controller interface to configure a channel. The plurality of pin resources  215  is coupled to circuitry for multiplexing among two or more high-speed interfaces (e.g., network and/or memory interfaces), specifically to flexibly allocate pins and/or bandwidth among the different high-speed interfaces. One or more signals of a channel may be uni-directional or bi-directional for transmitting data, clock, and/or control signals of an interface. The channels may support full duplex or half duplex transmissions. Furthermore, dynamic reconfiguration may also necessitate additional circuitry in the devices that are coupled to the channels, such as the router device  270  and the memory devices  230 . For example, the additional circuitry may include tri-state drivers to ensure that a communication channel of a router device  270  or a memory device  230  that is not enabled does not drive a wire connected to a shared pin on the processor device  220 . Although, the configurable pins resources are described as residing within the processor device  210 , persons skilled in the art will understand that other integrated circuit devices, such as the memory devices  230 , router device  270 , and/or another type of integrated circuit device may include configurable pin resources. 
       FIG. 3A  illustrates a pin resource  315  that is coupled to transmitter and receiver circuits for two different interfaces, in accordance with one embodiment. As shown in  FIG. 3A , only the pin resource  315  (e.g., pad coupled to a pin) is shared by a NIC interface and a memory controller (MC) interface. The pin resource  315  represents a single pad and pin rather than a plurality of pin resources that form a channel. A transmitter circuit  305  receives a signal from the NIC interface and the transmitter circuit  305  drives the signal to a pad within the pin resource  315  when the transmitter circuit  305  is enabled (i.e., when a transmit enable signal is asserted and a select NIC signal is asserted). When the transmitter circuit  305  is enabled, a signal is transmitted from a device that includes the pin resource  315  on a communication path of the NIC interface. A transmitter circuit  310  receives a signal from the MC interface and the transmitter circuit  310  drives the signal to the pin resource  315  when the transmitter circuit  310  is enabled (i.e., when a transmit enable signal is asserted and a select MC signal is asserted). When the transmitter circuit  310  is enabled, a signal is transmitted from the device that includes the pin resource  315  on a communication path of the MC interface. 
     When the select NIC signal is asserted, a first transistor configured as a pass gate connects a receiver circuit  325  to the pin resource  315 . The first transistor activates a path between the pad within the pin resource  315  and the receiver circuit  325  to receive a signal transmitted on a communication path of the NIC interface from a networking device to the device that includes the pin resource  315 . The receiver circuit  325  transmits the signal to the network interface controller  205 . 
     Likewise, when the select MC signal is asserted, a second transistor configured as a pass gate connects a receiver circuit  320  to the pin resource  315 . The second transistor activates a path between the pad within the pin resource  315  and the receiver circuit  320  to receive a signal transmitted on a communication path of the MC interface from a memory device to the device that includes the pin resource  315 . The receiver circuit  320  transmits the signal to the memory controller  210 . Separate transmitter circuits and receiver circuits for each interface may be required if the electrical signaling levels or the signal timing requirements are dramatically different between the external router device  225  or  270  and the memory devices  230 . 
       FIG. 3B  illustrates a pin resource  315  that is coupled to shared transmitter and receiver circuits for two different interfaces, in accordance with one embodiment. In one embodiment, the shared transmitter and receiver circuits may be configured to couple the pin resource  315  to additional interfaces. When the electrical and timing circuits are the same between two channels, the transmitter and receiver circuits can be shared for two different interfaces. A multiplexor is configured to select between a NIC interface input and a MC interface input based on the select NIC signal. The selected input is transmitted to the pin resource  315  by a transmitter circuit  355  when the transmit enable signal is asserted. The receiver circuit  360  routes the signal received by the pin resource  315  to both the NIC and MC interfaces as an input to the network interface controller  205  or memory controller  210 , whichever controller is enabled. The transmitter circuits and receiver circuits may be factored into subcomponents of which subsets (e.g., a pad of the pin resource  315 , at least a portion of the transmitter circuit  355 , and/or at least a portion of the receiver circuit  360 ) may be shared between two or more controller interfaces depending on the commonality of electrical and timing design. 
     In one embodiment, the interface between the network interface controller  205  and the router device  225  may operate at a higher frequency than a DRAM device or a non-volatile storage device, so the memory devices  230  include expansion circuitry to demultiplex signals received from the memory channel and multiplex signals that are output to the memory channel. In one embodiment, the expansion circuitry is implemented as a separate device that is coupled between the channel and the memory devices  230 . 
     A memory interface can be made wider in one of several manners. One technique, as shown in  FIGS. 2A and 2B , provides extra memory controllers  210  that are enabled when a wider memory interface is specified for the processor device  220 . When adding or subtracting memory controllers  210 , the internal architecture of the processor device  220  provides an adjustable address mapping mechanism that allows a memory address to be sent to different memory controllers  210  by processing units within the processor device  220  depending on the number of memory controllers  210  that are enabled, i.e., coupled to a memory device  230  via a plurality of pin resources  215 . 
     A second technique uses a fixed number of memory controllers  210 , but allows the width of the memory interface to be adjusted. For example, when more pin resources are available, the memory interface for a given memory controller  210  may be extended from 64 to 96 bits. Implementing interface width configurability may require the memory controller  210  to accept variable width transfers from the memory device  230  (e.g., DRAM) and to be able to change how the memory device burst size is divided into individual memory transfers. 
     The network architecture may support flexibility of use in different systems. For example, when additional pin resources are available, the number of network links (e.g., channels) may be kept fixed, but the width of each link may be increased. Implementing flexible link widths may require the network interface controllers  205  to support variable width network channels, and to be able to pack and unpack messages for different width channels. 
     Another optional technique for supporting flexibility is to keep the network channel width fixed and vary the number of network channels exposed to the network infrastructure outside of the processor device, i.e., the router device  225  or  270 . Such technique adjusts the number of network slices connected to the router device  225  or  270  and may require different numbers of routers for different systems. Modern system-level network topologies typically employ network slicing to increase path diversity and deliver better overall network bandwidth and performance than un-sliced networks. 
       FIG. 4A  illustrates another diagram of a system  400  including a processor device  420  with pin resources that provide a channel configuration, in accordance with one embodiment. The system  400  is similar to the system  200 , in that a plurality of pin resources  415 -B may be configured to provide a network channel or a memory channel. As shown in  FIG. 4A , the plurality of pin resources  415 -B has been split to increase the width of the memory interfaces between a memory controller  410 -B and a memory device  430 -B, and between a memory controller  410 -C and a memory device  430 -A. For example, the plurality of pin resources  415 -B may be split so that the memory interface width increases from 64 bits to 96 bits. The memory controllers  410 -B and  410 -C may be designed to operate the memory interface at variable width, for example at 32, 64, or 96 bits. A channel configuration unit  425  includes circuitry that configures the plurality of pin resources  415  based on the pin distribution to provide a specific memory and or network channel configuration. Therefore, a single integrated circuit may be used to implement the processor devices  220  and  420 . The single integrated circuit may be deployed to produce each of the systems  200 ,  250 , and  400 . In the system  400 , the extra memory controller  410 -A is disabled and may be gated off from a power supply and/or clock. The memory devices  430  may be implemented as dynamic random access memory (DRAM) devices or non-volatile memory or storage devices. 
       FIG. 4B  illustrates a flowchart  100  of a method for configuring a plurality of pin resources, in accordance with one embodiment. The operations  455 ,  460 , and  465  are performed in the same manner as operations  105 ,  110 , and  120 , as previously described in conjunction with  FIG. 1 . At operation  470 , the channel configuration unit  425  determines if the pin distribution has changed, and, if not, the configuration process terminates. The pin distribution may change in response to a change in a bandwidth requirement for one or more channels. Otherwise, channel configuration unit  425  returns to operation  460  to adjust the channel configuration based on the updated pin distribution. The channel configuration unit  425  may configure one or more sets of pin resources  215  or  415  to change from providing a memory channel to a network channel or vice versa. In one embodiment, the channel configuration unit  425  may split a plurality of pin resources  215  or  415  between one or more different channels to change the width of a channel. 
     In one embodiment, the plurality of pin resources are implemented to provide configurable channels through generic input/output (I/O) links as an extension to an on-chip network within the processor device  220 . More specifically, the I/O controllers (e.g., the NIC  205  and memory controller  210 ) are implemented on a different device or devices. These additional devices or device may be placed in the same package as the die containing the circuitry for the processor device  220 , or the additional devices or device may be located elsewhere on a system substrate (e.g., printed circuit board, silicon interposer, or multi-chip module substrate). In one embodiment, the additional devices or device may be included in a chip stack. 
       FIG. 5A  illustrates a diagram of a system  500  including a multi-processor device  520  with sets of pin resources  515  that provide a channel configuration using generic I/O links, in accordance with one embodiment. The multi-processor device  520  includes four processors  535 -A,  535 -B,  535 -C, and  535 -D that are connected to a network-on-chip (NOC)  535  that includes connections to external devices through sets of pin resources  515 . Two channels provided by the plurality of pin resources  515 -A and  515 -B connect two interfaces of the NOC  535  to a network interface controller device  505  that is coupled to a router device  525 . Two other channels that are provided by the plurality of pin resources  515 -C and  515 -D connect two other interfaces of the NOC  535  to one or more memory controller devices  510 -A and  510 -B that are coupled to memory devices  530 -A and  530 -B. The routing implemented by the NOC  535  may be changed based on the configuration of the sets of pin resources  515 , so that network communications are routed to a network channel and storage communications are routed to a memory channel. 
       FIG. 5B  illustrates another diagram of a system  550  including multi-processor device  520  with sets of pin resources  515  that provide a channel configuration using generic I/O links, in accordance with one embodiment. The system  550  includes an additional memory controller device  510 -C and a corresponding memory device  530 -C. The plurality of pin resources  515 -B provides a memory channel between the NOC  535  and the additional memory controller  510  instead of a network channel between the NOC  535  and the NIC device  505 . The electrical interfaces of the channels provided by the sets of pin resources  515 -A,  515 -B,  515 -C, and  515 -D are the same as for the system  500 , however address mapping tables within the multi-processor devices  520  are different to accommodate the additional memory controller device  510 . For example, memory traffic can be address interleaved across the two memory channels provided by the sets of pin resources  515 -C and  515 -D in the system  500  and across three memory channels provided by the sets of pin resources  515 -B,  515 -C, and  515 -D in the system  550 . Network traffic can be routed through either of the network channels provided by the sets of pin resources  515 -A and  515 -B in the system  500 . In system  550 , the network traffic can only be routed through the network channel provided by the plurality of pin resources  515 -A. 
     The channels provided by the sets of pin resources  215  or  515  may be reconfigured while a system is deployed in the field to transfer bandwidth capacity from the network devices to the storage system or from the storage system to the network devices. Dynamic reconfiguration capability may require extra network channels that can be enabled or disabled and/or extra memory channels that can be enabled or disabled. Dynamic reconfiguration capability may also require active circuits outside of the processor device  220  or multi-processor device  520  that selectively connect the network and memory channels to the sets of pin resources  215  and  515 , respectively. Because of the extra system costs associated with overprovisioning network bandwidth and memory bandwidth/capacity, supporting dynamic reconfiguration in the field may currently not be worthwhile in some systems. Instead, a variety of different configurations may be more commonly used to employ the same processor device  220  or multi-processor device  520  in systems that have different network and memory bandwidth demands. 
       FIG. 6  illustrates an exemplary system  600  in which the various architecture and/or functionality of the various previous embodiments may be implemented. As shown, a system  600  is provided including at least one central processor  601  that is connected to a communication bus  602 . The communication bus  602  may be implemented using any suitable protocol, such as PCI (Peripheral Component Interconnect), PCI-Express, AGP (Accelerated Graphics Port), HyperTransport, or any other bus or point-to-point communication protocol(s) between two or more of the system components (e.g., central processor  601 , main memory  604 , graphics processor  606 , display  608 , input devices  612 , secondary storage  610 , and the like). In one embodiment, one or more channels of the communication bus  602  may be implemented using channels that are configured based on a pin distribution using the process described in conjunction with  FIGS. 1 and/or 4B . The system  600  also includes a main memory  604 . Control logic (software) and data are stored in the main memory  604  which may take the form of random access memory (RAM). 
     The system  600  also includes input devices  612 , a graphics processor  606 , and a display  608 , i.e. a conventional CRT (cathode ray tube), LCD (liquid crystal display), LED (light emitting diode), plasma display or the like. User input may be received from the input devices  612 , e.g., keyboard, mouse, touchpad, microphone, and the like. In one embodiment, the graphics processor  606  may include a plurality of shader modules, a rasterization module, etc. 
     One or more of the components shown in  FIG. 6  may be included in a single semiconductor platform so that die or chips embodying the components are coupled to each other through a system substrate. In the present description, a system substrate may refer to a printed circuit board, multi-chip module substrate, silicon interposer, or a chip stack. Of course, the various components may also be situated separately or in various combinations of system platforms per the desires of the user. 
     The system  600  may also include a secondary storage  610 . The secondary storage  610  includes, for example, a hard disk drive and/or a removable storage drive, representing a floppy disk drive, a magnetic tape drive, a compact disk drive, digital versatile disk (DVD) drive, recording device, universal serial bus (USB) flash memory. The removable storage drive reads from and/or writes to a removable storage unit in a well-known manner. Computer programs, or computer control logic algorithms, may be stored in the main memory  604  and/or the secondary storage  610 . Such computer programs, when executed, enable the system  600  to perform various functions. The main memory  604 , the storage  610 , and/or any other storage are possible examples of computer-readable media. 
     In one embodiment, the architecture and/or functionality of the various previous figures may be implemented in the context of the central processor  601 , the graphics processor  606 , an integrated circuit (not shown) that is capable of at least a portion of the capabilities of both the central processor  601  and the graphics processor  606 , a chipset (i.e., a group of integrated circuits designed to work and sold as a unit for performing related functions, etc.), and/or any other integrated circuit for that matter. 
     Still yet, the architecture and/or functionality of the various previous figures may be implemented in the context of a general computer system, a circuit board system, a game console system dedicated for entertainment purposes, an application-specific system, and/or any other desired system. For example, the system  600  may take the form of a desktop computer, laptop computer, server, workstation, game consoles, embedded system, and/or any other type of logic. Still yet, the system  600  may take the form of various other devices including, but not limited to a personal digital assistant (PDA) device, a mobile phone device, a television, etc. 
     Further, while not shown, the system  600  may be coupled to a network (e.g., a telecommunications network, local area network (LAN), wireless network, wide area network (WAN) such as the Internet, peer-to-peer network, cable network, or the like) for communication purposes. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.