Abstract: A network processor includes a memory subsystem serving a plurality of processor cores. The memory subsystem includes a hierarchy of caches. A mid-level instruction cache provides for caching instructions for multiple processor cores. Likewise, a mid-level data cache provides for caching data for multiple cores, and can optionally serve as a point of serialization of the memory subsystem. A low-level cache is partitionable into partitions that are subsets of both ways and sets, and each partition can serve an independent process and/or processor core.

Abstract: A network processor includes a memory subsystem serving a plurality of processor cores. The memory subsystem includes a hierarchy of caches. A mid-level instruction cache provides for caching instructions for multiple processor cores. Likewise, a mid-level data cache provides for caching data for multiple cores, and can optionally serve as a point of serialization of the memory subsystem. A low-level cache is partitionable into partitions that are subsets of both ways and sets, and each partition can serve an independent process and/or processor core.

Abstract: A network processor includes a cache and a several groups of processors for accessing the cache. A memory interconnect provides for connecting the processors to the cache via a plurality of memory buses. A number of trace buffers are also connected to the bus and operate to store information regarding commands and data transmitted across the bus. The trace buffers share a common address space, thereby enabling access to the trace buffers as a single entity.

Abstract: According to at least one example embodiment, a method and corresponding apparatus for conditionally storing data include initiating an atomic sequence by executing, by a core processor, an instruction/operation designed to initiate an atomic sequence. Executing the instruction designed to initiate the atomic sequence includes loading content associated with a memory location into a first cache memory, and maintaining an indication of the memory location and a copy of the corresponding content loaded. A conditional storing operation is then performed, the conditional storing operation includes a compare-and-swap operation, executed by a controller associated with a second cache memory, based on the maintained copy of the content and the indication of the memory location.

Abstract: A multi-chip system includes multiple chip devices configured to communicate to each other and share resources. According to at least one example embodiment, a method of providing memory coherence within the multi-chip system comprises maintaining, at a first chip device of the multi-chip system, state information indicative of one or more states of one or more copies, residing in one or more chip devices of the multi-chip system, of a data block. The data block is stored in a memory associated with one of the multiple chip devices. The first chip device receives a message associated with a copy of the one or more copies of the data block from a second chip device of the multiple chip devices, and, in response, executes a scheme of one or more actions determined based on the state information maintained at the first chip device and the message received.

Abstract: A network processor includes multiple processor cores for processing packet data. In order to provide the processor cores with access to a memory subsystem, an interconnect circuit directs communications between the processor cores and the L2 Cache and other memory devices. The processor cores are divided into several groups, each group sharing an individual bus, and the L2 Cache is divided into a number of banks, each bank having access to a separate bus. The interconnect circuit processes requests to store and retrieve data from the processor cores across multiple buses, and processes responses to return data from the cache banks. As a result, the network processor provides high-bandwidth memory access for multiple processor cores.

Abstract: A network services processor includes an input/output bridge that avoids unnecessary updates to memory when cache blocks storing processed packet data are no longer required. The input/output bridge monitors requests to free buffers in memory received from cores and IO units in the network services processor. Instead of writing the cache block back to the buffer in memory that will be freed, the input/output bridge issues don't write back commands to a cache controller to clear the dirty bit for the selected cache block, thus avoiding wasteful write-backs from cache to memory. After the dirty bit is cleared, the buffer in memory is freed, that is, made available for allocation to store data for another packet.

Abstract: According to at least one example embodiment, a method of data coherence is employed within a multi-chip system to enforce cache coherence between chip devices of the multi-node system. According at least one example embodiment, a message is received by a first chip device of the multiple chip devices from a second chip device of the multiple chip devices. The message triggers invalidation of one or more copies, if any, of a data block. The data block stored in a memory attached to, or residing in, the first chip device. Upon determining that one or more remote copies of the data block are stored in one or more other chip devices, other than the first chip device, the first chip device sends one or more invalidation requests to the one or more other chip devices for invalidating the one or more remote copies of the data block.

Abstract: A multi-chip system includes multiple chip devices configured to communicate to each other and share resources. According to at least one example embodiment, a method of providing memory coherence within the multi-chip system comprises maintaining, at a first chip device of the multi-chip system, state information indicative of one or more states of one or more copies, residing in one or more chip devices of the multi-chip system, of a data block. The data block is stored in a memory associated with one of the multiple chip devices. The first chip device receives a message associated with a copy of the one or more copies of the data block from a second chip device of the multiple chip devices, and, in response, executes a scheme of one or more actions determined based on the state information maintained at the first chip device and the message received.

Abstract: According to at least one example embodiment, a method and corresponding apparatus for conditionally storing data include initiating an atomic sequence by executing, by a core processor, an instruction/operation designed to initiate an atomic sequence. Executing the instruction designed to initiate the atomic sequence includes loading content associated with a memory location into a first cache memory, and maintaining an indication of the memory location and a copy of the corresponding content loaded. A conditional storing operation is then performed, the conditional storing operation includes a compare-and-swap operation, executed by a controller associated with a second cache memory, based on the maintained copy of the content and the indication of the memory location.

Abstract: A network services processor includes an input/output bridge that avoids unnecessary updates to memory when cache blocks storing processed packet data are no longer required. The input/output bridge monitors requests to free buffers in memory received from cores and IO units in the network services processor. Instead of writing the cache block back to the buffer in memory that will be freed, the input/output bridge issues don't write back commands to a cache controller to clear the dirty bit for the selected cache block, thus avoiding wasteful write-backs from cache to memory. After the dirty bit is cleared, the buffer in memory is freed, that is, made available for allocation to store data for another packet.

Abstract: In one embodiment, a system includes a memory and a first bridge unit for processor access with the memory coupled with an input-output bus and the memory. The first bridge unit is configured to receive requests from the input-output bus to read or write data receive requests from the MFNU to free memory and choose among the requests to send to the memory on a first memory bus. The system also includes a second bridge unit for packet data access with the memory coupled with a packet input unit, packet output unit, and the memory. The second bridge unit is configured to receive requests to write packet data from the packet input unit, receive requests to read packet data from the packet output unit, and choose among the requests from the packet input unit and the packet output unit to send to the memory on a second memory bus.

Abstract: In one embodiment, a system includes a memory and a first bridge unit for processor access with the memory coupled with an input-output bus and the memory. The first bridge unit is configured to receive requests from the input-output bus to read or write data receive requests from the MFNU to free memory and choose among the requests to send to the memory on a first memory bus. The system also includes a second bridge unit for packet data access with the memory coupled with a packet input unit, packet output unit, and the memory. The second bridge unit is configured to receive requests to write packet data from the packet input unit, receive requests to read packet data from the packet output unit, and choose among the requests from the packet input unit and the packet output unit to send to the memory on a second memory bus.

Abstract: In one embodiment, a system comprises a memory, and a first bridge unit for processor access with the memory. The first bridge unit comprises a first arbitration unit that is coupled with an input-output bus, a memory free notification unit (“MFNU”), and the memory, and is configured to receive requests from the input-output bus and receive requests from the MFNU and choose among the requests to send to the memory on a first memory bus. The system further comprises a second bridge unit for packet data access with the memory that includes a second arbitration unit that is coupled with a packet input unit, a packet output unit, and the memory and is configured to receive requests from the packet input unit and receive requests from the packet output unit, and choose among the requests to send to the memory on a second memory bus.

Abstract: A network processor includes multiple processor cores for processing packet data. In order to provide the processor cores with access to a memory subsystem, an interconnect circuit directs communications between the processor cores and the L2 Cache and other memory devices. The processor cores are divided into several groups, each group sharing an individual bus, and the L2 Cache is divided into a number of banks, each bank having access to a separate bus. The interconnect circuit processes requests to store and retrieve data from the processor cores across multiple buses, and processes responses to return data from the cache banks. As a result, the network processor provides high-bandwidth memory access for multiple processor cores.

Abstract: A network processor includes a cache and a several groups of processors for accessing the cache. A memory interconnect provides for connecting the processors to the cache via a plurality of memory buses. A number of trace buffers are also connected to the bus and operate to store information regarding commands and data transmitted across the bus. The trace buffers share a common address space, thereby enabling access to the trace buffers as a single entity.

Abstract: In one embodiment, a system comprises a memory, and a first bridge unit for processor access with the memory. The first bridge unit comprises a first arbitration unit that is coupled with an input-output bus, a memory free notification unit (“MFNU”), and the memory, and is configured to receive requests from the input-output bus and receive requests from the MFNU and choose among the requests to send to the memory on a first memory bus. The system further comprises a second bridge unit for packet data access with the memory that includes a second arbitration unit that is coupled with a packet input unit, a packet output unit, and the memory and is configured to receive requests from the packet input unit and receive requests from the packet output unit, and choose among the requests to send to the memory on a second memory bus.

Abstract: A RISC-type processor includes a main register file and a data cache. The data cache can be partitioned to include a local memory, the size of which can be dynamically changed on a cache block basis while the processor is executing instructions that use the main register file. The local memory can emulate as an additional register file to the processor and can reside at a virtual address. The local memory can be further partitioned for prefetching data from a non-cacheable address to be stored/loaded into the main register file.

Abstract: A method and apparatus for minimizing stalls in a pipelined processor is provided. Instructions in an out-of-order instruction scheduler are executed in order without stalling the pipeline by sending store data to external memory through an ordering queue.

Abstract: A method and architecture for improving the usability and manufacturing yield of a microprocessor having a large on-chip n-way set associative cache. The architecture provides a method for working around defects in the portion of the die allocated to the data array of the cache. In particular, by adding a plurality of muxes to a way or ways in the data array of an associative cache having the shorter paths to the access control logic, each way in a bank can be selectively replaced or remapped to the ways with the shorter paths without adding any latency to the system. This selective remapping of separate ways in individual banks of the set associative cache provides a more efficient way to absorb defects and allows more defects to be absorbed in the data array of a set associative cache.