Abstract: Embodiments are described for methods and systems for mapping virtual memory pages to physical memory pages by analyzing a sequence of memory-bound accesses to the virtual memory pages, determining a degree of contiguity between the accessed virtual memory pages, and mapping sets of the accessed virtual memory pages to respective single physical memory pages. Embodiments are also described for a method for increasing locality of memory accesses to DRAM in virtual memory systems by analyzing a pattern of virtual memory accesses to identify contiguity of accessed virtual memory pages, predicting contiguity of the accessed virtual memory pages based on the pattern, and mapping the identified and predicted contiguous virtual memory pages to respective single physical memory pages.

Abstract: A system may determine that a processor has powered up. The system may determine a first prefetching policy based on determining that the processor has powered up. The system may fetch information, from a main memory and for storage by a cache associated with the processor, using the first prefetching policy. The system may determine, after fetching information using the first prefetching policy, to apply a second prefetching policy that is different than the first prefetching policy. The system may fetch information, from the main memory and for storage by the cache, using the second prefetching policy.

Abstract: A system and method for efficiently limiting storage space for data with particular properties in a cache memory. A computing system includes a cache array and a corresponding cache controller. The cache array includes multiple banks, wherein a first bank is powered down. In response a write request to a second bank for data indicated to be stored in the powered down first bank, the cache controller determines a respective bypass condition for the data. If the bypass condition exceeds a threshold, then the cache controller invalidates any copy of the data stored in the second bank. If the bypass condition does not exceed the threshold, then the cache controller stores the data with a clean state in the second bank. The cache controller writes the data in a lower-level memory for both cases.

Abstract: A multi-core data processor includes multiple data processor cores and a power controller. Each data processor core has a first input for receiving a clock signal, a second input for receiving a power supply voltage, and an output for providing an idle signal. The power controller is coupled to each of the data processor cores for providing the clock signal and the power supply voltage to each of the data processor cores. The power controller provides at least one of the clock signal and the power supply voltage to an active one of the data processor cores in dependence on a number of idle signals received from the data processor cores.

Abstract: A method includes controlling active frequency states of a plurality of heterogeneous processing units based on frequency sensitivity metrics indicating performance coupling between different types of processing units in the plurality of heterogeneous processing units. A processor includes a plurality of heterogeneous processing units and a performance controller to control active frequency states of the plurality of heterogeneous processing units based on frequency sensitivity metrics indicating performance coupling between different types of processing units in the plurality of heterogeneous processing units. The active frequency state of a first type of processing unit in the plurality of heterogeneous processing units is controlled based on a first activity metric associated with a first type of processing unit and a second activity metric associated with a second type of processing unit.

Abstract: A cache memory receives a request to perform a write operation. The request specifies an address. A first determination is made that the cache memory does not include a cache line corresponding to the address. A second determination is made that the address is between a previous value of a stack pointer and a current value of the stack pointer. A third determination is made that a write history indicator is set to a specified value. The write operation is performed in the cache memory without waiting for a cache fill corresponding to the address to be performed, in response to the first, second, and third determinations.

Abstract: A method and apparatus for exiting a low power state based on a prior prediction is disclosed. An integrated circuit (IC) includes a functional unit configured to, during operation, cycle between intervals of an active state and intervals of an idle state. The IC also include a power management unit configured to place the functional unit in a low power state responsive to the functional unit entering the idle state. The power management unit is further configured to preemptively cause the functional unit to exit the low power state at a predetermined time after entering the low power. The predetermined time is based on a prediction of idle state duration made prior to entering the low power state. The prediction may be generated by a prediction unit, based on a history of durations of intervals in which the functional unit was in the idle state.

Abstract: Durations of active performance states of components of a processing system can be predicted based on one or more previous durations of an active state of the components. One or more entities in the processing system such as processor cores or caches can be configured based on the predicted durations of the active state of the components. Some embodiments configure a first component in a processing system based on a predicted duration of an active state of a second component of the processing system. The predicted duration is predicted based on one or more previous durations of an active state of the second component.

Abstract: A circuit includes a plurality of synchronizers to adapt a signal from a first clock domain to a second clock domain. Each synchronizer of the plurality of synchronizers includes a synchronizer input to receive the signal from the first clock domain and a synchronizer output to provide the signal as adapted to the second clock domain. The circuit also includes a multiplexer (mux) that includes a plurality of mux inputs and a mux output. Each mux input is coupled to the synchronizer output of a respective synchronizer of the plurality of synchronizers. The mux output provides the signal, as adapted to the second clock domain, from the synchronizer output of a selected synchronizer of the plurality of synchronizers.

Abstract: Power gating decisions can be made based on measures of cache dirtiness. Analyzer logic can selectively power gate a component of a processor system based on a cache dirtiness of one or more caches associated with the component. The analyzer logic may power gate the component when the cache dirtiness exceeds a threshold and may maintains the component in an idle state when the cache dirtiness does not exceed the threshold. Idle time prediction logic may be used to predict a duration of an idle time of the component. The analyzer logic may then selectively power gates the component based on the cache dirtiness and the predicted idle time.

Abstract: One or more lines of a cache are prefetched according to a first prefetch routine while training a prefetcher to prefetch one or more lines of the cache according to a second prefetch routine. In response to determining that the prefetcher has been trained, one or more lines of the cache may be prefetched according to the second prefetch routine.

Abstract: In response to a processor core exiting a low-power state, a cache is set to a minimum size so that fewer than all of the cache's entries are available to store data, thus reducing the cache's power consumption. Over time, the size of the cache can be increased to account for heightened processor activity, thus ensuring that processing efficiency is not significantly impacted by a reduced cache size. In some embodiments, the cache size is increased based on a measured processor performance metric, such as an eviction rate of the cache. In some embodiments, the cache size is increased at regular intervals until a maximum size is reached.

Abstract: A data processing system includes a plurality of processor resources, a manager, and a power distributor. Each of the plurality of data processor cores is operable at a selected one of a plurality of performance states. The manager assigns each of a plurality of program elements to one of the plurality of processor resources, and synchronizing the program elements using barriers. The power distributor is coupled to the manager and to the plurality of processor resources, and assigns a performance state to each of the plurality of processor resources within an overall power budget, and in response to detecting that a program element assigned to a first processor resource is at a barrier, increases the performance state of a second processor resource that is not at the barrier within the overall power budget.

Abstract: A level of cache memory receives modified data from a higher level of cache memory. A set of cache lines with an index associated with the modified data is identified. The modified data is stored in the set in a cache line with an eviction priority that is at least as high as an eviction priority, before the modified data is stored, of an unmodified cache line with a highest eviction priority among unmodified cache lines in the set.

Abstract: In some embodiments, a method of managing cache memory includes identifying a group of cache lines in a cache memory, based on a correlation between the cache lines. The method also includes tracking evictions of cache lines in the group from the cache memory and, in response to a determination that a criterion regarding eviction of cache lines in the group from the cache memory is satisfied, selecting one or more (e.g., all) remaining cache lines in the group for eviction.

Abstract: A system and method for efficient predicting and processing of memory access dependencies. A computing system includes control logic that marks a detected load instruction as a first type responsive to predicting the load instruction has high locality and is a candidate for store-to-load (STL) data forwarding. The control logic marks the detected load instruction as a second type responsive to predicting the load instruction has low locality and is not a candidate for STL data forwarding. The control logic processes a load instruction marked as the first type as if the load instruction is dependent on an older store operation. The control logic processes a load instruction marked as the second type as if the load instruction is independent on any older store operation.

Abstract: A cache memory receives a request to perform a write operation. The request specifies an address. A first determination is made that the cache memory does not include a cache line corresponding to the address. A second determination is made that the address is between a previous value of a stack pointer and a current value of the stack pointer. A third determination is made that a write history indicator is set to a specified value. The write operation is performed in the cache memory without waiting for a cache fill corresponding to the address to be performed, in response to the first, second, and third determinations.

Abstract: A system and method for efficiently limiting storage space for data with particular properties in a cache memory. A computing system includes a cache array and a corresponding cache controller. The cache array includes multiple banks, wherein a first bank is powered down. In response a write request to a second bank for data indicated to be stored in the powered down first bank, the cache controller determines a respective bypass condition for the data. If the bypass condition exceeds a threshold, then the cache controller invalidates any copy of the data stored in the second bank. If the bypass condition does not exceed the threshold, then the cache controller stores the data with a clean state in the second bank. The cache controller writes the data in a lower-level memory for both cases.

Abstract: In response to a processor core exiting a low-power state, a cache is set to a minimum size so that fewer than all of the cache's entries are available to store data, thus reducing the cache's power consumption. Over time, the size of the cache can be increased to account for heightened processor activity, thus ensuring that processing efficiency is not significantly impacted by a reduced cache size. In some embodiments, the cache size is increased based on a measured processor performance metric, such as an eviction rate of the cache. In some embodiments, the cache size is increased at regular intervals until a maximum size is reached.

Abstract: A multi-core data processor includes multiple data processor cores and a circuit. The multiple data processor cores each include a power state controller having a first input for receiving an idle signal, a second input for receiving a release signal, a third input for receiving a control signal, and an output for providing a current power state. In response to the idle signal, the power state controller causes a corresponding data processor core to enter an idle state. In response to the release signal, the power state controller changes the current power state from the idle state to an active state in dependence on the control signal. The circuit is coupled to each of the multiple data processor cores for providing the control signal in response to current power states in the multiple data processor cores.