Methods and apparatus for caching information associated with packets are disclosed. According to one aspect of the present invention, a system for processing a packet includes a controller with a processor and a controller data cache, a bus, a memory interface, and a separate data cache. The memory interface may be accessed by the controller via the bus, and is arranged to be in communication with a substantially external memory. The separate data cache, which is also in communication with the controller via the bus, caches information associated with the packet such that the controller accesses the separate data cache to obtain the information associated with the packet when the controller needs to decide how to process the packet.
A method and apparatus for a cache line cut through reduces the latency and memory bandwidth of a data processing system. By cutting through or forwarding a cache line to the next processing element, data that has been read from a local memory into a local cache and altered by a processing element need not be restored to the local memory before it is sent to its destination target processing element. By eliminating the write back to the local memory for direct write through to the destination, performance is increased because the bandwidth and latency are decreased. In a preferred embodiment, the processing elements may be contained within a network processor and the altered data may be a header in one network protocol which needs to be modified to another protocol before transfer of the data along the network. Transfer of the data may be to another network processor, another processing element, or to another memory.
