Multi-core interconnect in a network processor
View Patent ↗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.
1. A computer system on a computer chip comprising:
an interconnect circuit;
a plurality of memory buses, each bus connecting a respective group of plural processor cores to the interconnect circuit; and
a cache divided into a plurality of banks, each bank being connected to the interconnect circuit via an individual bus;
the interconnect circuit configured to distribute a plurality of requests received from the plural processor cores among the plurality of banks, wherein the interconnect circuit transforms the requests by modifying an address component of the requests.
2. The system of claim 1 , wherein the interconnect circuit performs a hash function on each of the requests, the hash function providing a pseudo-random distribution of the requests among the plurality of banks.
3. The system of claim 1 , wherein the interconnect circuit is configured to maintain tags indicating a state of an L1 cache coupled to one of the plural processor cores, and wherein the interconnect circuit is further configured to direct tags in the plurality of requests to a plurality of channels thereby processing the respective tags concurrently.
4. The system of claim 1 , wherein the interconnect circuit further comprises a plurality of data output buffers, each of the data output buffers configured to receive data from each of the plurality of banks and output data through a respective one of the plurality of memory buses.
5. The system of claim 1 , wherein the interconnect circuit further comprises a plurality of request buffers, each of the request buffers configured to receive requests from each group of plural processors and output the request to a respective one of the plurality of banks.
6. The system of claim 1 , further comprising at least one bridge circuit coupled to at least one of the memory buses, the at least one bridge circuit connecting the plural processor cores to at least one on-chip co-processor.
7. The system of claim 1 , wherein the banks are configured to delay transmitting a commit signal to the plural processor cores, the banks transmitting the commit signal in response to receiving an indication that invalidate signals have been transmitted to the entirety of the plural processor cores.
8. The system of claim 1 , wherein the interconnect circuit and plurality of memory buses are configured to control invalidates to reach an L1 cache in less time than a time required for a commit to reach one of the plurality of banks and a subsequent signal to reach one of the plural processor cores receiving the invalidate.