Abstract: A method and apparatus for dynamically controlling a cache size is disclosed. In one embodiment, a method includes changing an operating point of a processor from a first operating point to a second operating point, and selectively removing power from one or more ways of a cache memory responsive to changing the operating point. The method further includes processing one or more instructions in the processor subsequent to removing power from the one or more ways of the cache memory, wherein said processing includes accessing one or more ways of the cache memory from which power was not removed.

Abstract: A method for power management is disclosed. The method may include monitoring requests for access to a memory of a memory subsystem by one or more processor cores; and monitoring requests for access to the memory conveyed by an input/output (I/O) unit. The method may further include determining if at least a first amount of time has elapsed since any one of the processor cores has asserted a memory access request and determining if at least a second amount of time has elapsed since the I/O unit has conveyed a memory access request. A first signal may be asserted if the first and second amounts of time have elapsed. A memory subsystem may be transitioned from operating in a full power state to a first low power state responsive to assertion of the first signal.

Abstract: Embodiments of the invention provide an algorithm for dividing a link into one or more reduced-width links. For one embodiment of the invention, a multiplexing scheme is employed to effect a bit transmission order required by a particular cyclic redundancy check. The multiplexed output bits are then swizzled on-chip to reduce on-board routing congestion.

Abstract: A processing node tracks probe activity level associated with its internal caching or memory system. If the probe activity level increases above a threshold probe activity level, the performance state of the processing node is increased above its current performance state to provide enhanced performance capability in responding to the probe requests. After entering the higher performance state in response to the probe activity level being above the threshold probe activity level, the processing nodes returns to a lower performance state in response to a reduction in probe activity. There may be multiple threshold probe activity levels and associated performance states.

Abstract: A processing node tracks probe activity level associated with its cache. The processing node and/or processing system further predicts an idle duration. If the probe activity level increases above a threshold probe activity level, and the idle duration prediction is above a threshold idle duration threshold, the processing node flushes its cache to prevent probes to the cache. If the probe activity level is above the threshold probe activity level but the predicted idle duration is too short, the performance state of the processing node is increased above its current performance state to provide enhanced performance capability in responding to the probe requests.

Abstract: A method for transitioning power states in a device includes designating a first reduced power state as a target power state. A first expected residency for the target power state is determined based on a counting of activity requests associated with the device. The device is transitioned to the target power state responsive to the expected residency satisfying a first predetermined threshold.

Abstract: A technique is described by which two link agents with ports coupled together using a point-to-point interconnect in a system exchange their link width support capabilities and negotiate a link width that is mutually agreeable. The interconnect between each pair of agents comprises a pair of uni-directional links having multiple electrical wires, or lanes, where one link is used by a first agent to transmit data to a second agent and another link is used by the second agent to transmit data to the first agent.

Abstract: A processor integrated circuit has one or more processor cores and a power management controller in a North-Bridge that generates a first power state recommendation for the one or more processor cores. The North-Bridge also receives a second power state recommendation from a South-Bridge integrated circuit. The North-Bridge determines a final power state for the one or more processor cores based on the first and second power state recommendations.

Abstract: A hierarchical memory request stream arbitration technique merges coherent memory request streams from multiple memory request sources and arbitrates the merged coherent memory request stream with requests from a non-coherent memory request stream. In at least one embodiment of the invention, a method of generating a merged memory request stream from a plurality of memory request streams includes merging coherent memory requests into a first serial memory request stream. The method includes selecting, by a memory controller circuit, a memory request for placement in the merged memory request stream from at least the first serial memory request stream and a merged non-coherent request stream. The merged non-coherent memory request stream is at least partially based on an indicator of a previous memory request selected for placement in the merged memory request stream.

Abstract: In one embodiment, a system comprises a memory; a memory interface coupled to the memory; a processor unit coupled to the memory interface, a second interface coupled to the processor unit, and a graphics processing unit. The processor unit comprises at least one processor core and a display controller configured to couple to a display. The graphics processing unit is configured to render data into a frame buffer representing an image to be displayed on the display. The processor unit is configured to deactivate the second interface if the graphics processing unit is not rendering, and the display controller is configured to read the frame buffer data for display even if the second interface is deactivated.

Abstract: A method for determining an operating point of a shared resource. The method includes receiving indications of access demand to a shared resource from each of a plurality of functional units and determining a maximum access demand from among the plurality of functional units based on their respective indications. The method further includes determining a required operating point of the shared resource based on the maximum access demand, wherein the shared resource is shared by each of the plurality of functional units, comparing the required operating point to a present operating point of the shared resource, and changing to the required operating point from the present operating point if the required and present operating points are different.

Abstract: A system may comprise a plurality of processing units, and a control unit and monitoring unit interfacing with the processing units. The control unit may receive requests for transitioning the processing units to respective target power-states, and specify respective target HW power-states corresponding to the respective target power-states. The monitoring unit may monitor operating characteristics of the system, and determine based on operating characteristics whether to allow the processing units to transition to the respective target hardware (HW) power-states. The control unit may be configured to change the respective target HW power-state to a respective updated HW power-state for each processing units for which it is determined that transition to its respective target HW power-state should not be allowed.

Abstract: A system may comprise a plurality of processing units and a scheduler configured to maintain a record for each respective processing unit. Each respective record may comprise entries which may indicate 1) how long the respective processing unit has been residing in an idle state, 2) a present power-state in which the respective processing unit resides, and 3) whether the respective processing unit is a designated default (bootstrap) processing unit. The scheduler may select one or more of the plurality of processing units according to their respective records, and assign impending instructions to be executed on the selected one or more processing units. Where additional processing units are required, the scheduler may also insert an instruction to trigger an inter-processor interrupt to transition one or more processing units out of idle-state. The scheduler may then assign some impending instructions to these one or more processing units.

Abstract: In one embodiment, the present invention includes a method for receiving data from a second device in a first device, forwarding the data from an input/output (I/O) clock domain to a system clock domain of the first device, and providing the data to a functional unit of the first device at a deterministic time. In such manner, the two devices may operate in lockstep fashion. Other embodiments are described and claimed.

Abstract: Methods and apparatuses for determining clock failure for a multi-agent system employing a link-based interconnection scheme using a forwarded clock. For one embodiment of the invention, the cessation of the forwarded clock initiates a clock failure determination process. For one embodiment of the invention, upon a determination of clock failure, an alternate clock lane is implemented using a pre-designated data lane.

Abstract: A computer system comprising a memory system that comprises a plurality of memory modules; and a memory controller that accesses the plurality of memory modules to service memory requests. The computer system also comprises an error-type memory controller that configures the noted access such that the memory controller can continue to access a failed one of the plurality of memory modules that incurred a soft error.

Abstract: A computer system has a memory controller that includes read buffers coupled to a plurality of memory channels. The memory controller advantageously eliminates the inter-channel skew caused by memory modules being located at different distances from the memory controller. The memory controller preferably includes a channel interface and synchronization logic circuit for each memory channel. This circuit includes read and write buffers and load and unload pointers for the read buffer. Unload pointer logic generates the unload pointer and load pointer logic generates the load pointer. The pointers preferably are free-running pointers that increment in accordance with two different clock signals. The load pointer increments in accordance with a clock generated by the memory controller but that has been routed out to and back from the memory modules.

Abstract: An efficient system and method for managing reads and writes on a bi-directional bus to optimize bus performance while avoiding bus contention and avoiding read/write starvation. In particular, by intelligently managing reads and writes on a bi-directional bus, bus latency can be reduced while still ensuring no bus contention or read/write starvation. This is accomplished by utilizing bus streaming control logic, separate queues for reads and writes, and a simple 2 to 1 mux.

Abstract: An efficient system and method for managing reads and writes on a bi-directional bus to optimize bus performance while avoiding bus contention and avoiding read/write starvation. In particular, by intelligently managing reads and writes on a bi-directional bus, bus latency can be reduced while still ensuring no bus contention or read/write starvation. This is accomplished by utilizing bus streaming control logic, separate queues for reads and writes, and a simple 2 to 1 mux.

Abstract: A method and architecture for improved system resource management and allocation for the processing of request and response messages in a computer system. The resource management scheme provides for dynamically sharing system resources, such as data buffers, between request and response messages or transactions. In particular, instead of simply dedicating a portion of the system resources to requests and the remaining portion to responses, a minimum amount of resources are reserved for responses and a minimum amount for requests, while the remaining resources are dynamically shared between both types of messages. The method and architecture of the present invention allows for more efficient use of system resources, while avoiding deadlock conditions and ensuring a minimum service rate for requests.