Abstract:
An apparatus for processing cache requests in a computing system is disclosed. The apparatus may include a plurality of state memories, a plurality tag memories, and a control circuit. Each of the state memories may be configured to store coherency state information for a cache memory of a respective plurality of coherent agents. Each of the tag memories may be configured to store duplicate tag information a cache memory of the respective plurality of coherent agents. The control circuit may be configured to receive a tag address, access tag information in each of the tag memories in parallel dependent upon the received tag address, determine, for each cache memory, new coherency state information for a cache entry corresponding to the received tag address, and store the new coherency state information for each of the cache memories into a respective one of the plurality of state memories.
Abstract:
An apparatus for processing cache requests in a computing system is disclosed. The apparatus may include a single-port memory, a dual-port memory, and a control circuit. The single-port memory may be store tag information associated with a cache memory, and the dual-port memory may be configured to store state information associated with the cache memory. The control circuit may be configured to receive a request which includes a tag address, access the tag and state information stored in the single-port memory and the dual-port memory, respectively, dependent upon the received tag address. A determination of if the data associated with the received tag address is contained in the cache memory may be made the control circuit, and the control circuit may update and store state information in the dual-port memory responsive to the determination.
Abstract:
Techniques are disclosed relating to reducing power consumption in integrated circuits. In one embodiment, an apparatus includes a cache having a set of tag structures and a power management unit. The power management unit is configured to power down a duplicate set of tag structures in responsive to the cache being powered down. In one embodiment, the cache is configured to provide, to the power management unit, an indication of whether the cache includes valid data. In such an embodiment, the power management unit is configured to power down the cache in response to the cache indicating that the cache does not include valid data. In some embodiments, the duplicate set of tag structures is located within a coherence point configured to maintain coherency between the cache and a memory.
Abstract:
Systems, apparatuses, and methods for performing coherence processing and memory cache processing in parallel are disclosed. A system includes a communication fabric and a plurality of dual-processing pipelines. Each dual-processing pipeline includes a coherence processing pipeline and a memory cache processing pipeline. The communication fabric forwards a transaction to a given dual-processing pipeline, with the communication fabric selecting the given dual-processing pipeline, from the plurality of dual-processing pipelines, based on a hash of the address of the transaction. The given dual-processing pipeline performs a duplicate tag lookup in parallel with a memory cache tag lookup for the transaction. By performing the duplicate tag lookup and the memory cache tag lookup in a parallel fashion rather than in a serial fashion, latency and power consumption are reduced while performance is enhanced.
Abstract:
A method and apparatus for power management of cache duplicate tags is disclosed. An IC includes a cache, a coherence circuit, and a duplicate tags memory that may store duplicates of the tags stored in the cache. The cache includes a number of ways that are separately and independently power controllable. The duplicate tags memory may be similarly organized, with portions that are power controllable separately and independently of others. The coherence circuit is also power controllable, and may be placed into a sleep mode when idle. The IC also includes a power management circuit. During operation, the cache may change power states and provide a corresponding indication to the power management circuit. Responsive to the indication, the power management circuit may awaken the coherence circuit if in a sleep state. The coherence circuit may then power manage the duplicate tags in accordance with the change in power state.
Abstract:
A method and apparatus for power management of cache duplicate tags is disclosed. An IC includes a cache, a coherence circuit, and a duplicate tags memory that may store duplicates of the tags stored in the cache. The cache includes a number of ways that are separately and independently power controllable. The duplicate tags memory may be similarly organized, with portions that are power controllable separately and independently of others. The coherence circuit is also power controllable, and may be placed into a sleep mode when idle. The IC also includes a power management circuit. During operation, the cache may change power states and provide a corresponding indication to the power management circuit. Responsive to the indication, the power management circuit may awaken the coherence circuit if in a sleep state. The coherence circuit may then power manage the duplicate tags in accordance with the change in power state.
Abstract:
Techniques are disclosed relating to reducing power consumption in integrated circuits. In one embodiment, an apparatus includes a cache having a set of tag structures and a power management unit. The power management unit is configured to power down a duplicate set of tag structures in responsive to the cache being powered down. In one embodiment, the cache is configured to provide, to the power management unit, an indication of whether the cache includes valid data. In such an embodiment, the power management unit is configured to power down the cache in response to the cache indicating that the cache does not include valid data. In some embodiments, the duplicate set of tag structures is located within a coherence point configured to maintain coherency between the cache and a memory.
Abstract:
A coherence system includes a storage array that may store duplicate tag information associated with a cache memory of a processor. The system may also include a pipeline unit that includes a number of stages to control accesses to the storage array. The pipeline unit may pass through the pipeline stages, without generating an access to the storage array, an input/output (I/O) request that is received on a fabric. The system may also include a debug engine that may reformat the I/O request from the pipeline unit into a debug request. The debug engine may send the debug request to the pipeline unit via a debug bus. In response to receiving the debug request, the pipeline unit may access the storage array. The debug engine may return to the source of the I/O request via the fabric bus, a result of the access to the storage array.