System and method for prioritized context switching for streaming data memory transfers

Abstract

Method of streaming data transfers from scattered locations or to a gathered location in a memory, including the steps of manipulating the transfer of data between memory devices by processing, an element at a time, entries in a first scatter/gather list; upon receipt of a request to process a second scatter/gather list, interrupting the processing of the first list; and resuming the processing of the first list upon the completion of the processing of the second. In one embodiment, the step of interrupting the processing of the first scatter gather list interrupts only at the completion of the processing of an element of the first scatter/gather list and prior to the retrieval of the next element in the first scatter/gather list. In another embodiment, the interrupting step further includes storing the next address to be processed in the first scatter/gather list, and retrieving the first element in the second scatter/gather list. Provides a scatter/gather mechanism for streaming transfers between a first and second memory device without processor or firmware intervention. The mechanism comprises: a transfer engine for streaming data transfers between dispersed locations in one memory to a gathered location in a second memory, means for suspending processing of a current transfer request upon the receipt of a second request, and means for resuming the processing of a suspended transfer request including a pointer for indicating the starting address of a next element to be processed in a suspended transfer operation. Computer program and computer program product are also provided.