SYSTEM METHOD FOR DETERMINISTIC MESSAGE PROCESSING A DIRECT MEMORY ACCESS (DMA) ADAPTER WITH HEAD POINTERS AND TAIL POINTERS FOR DETERMINING THE IN AND OUT SEQUENCE OF PACKETS

摘要

Deterministic message processing in a direct memory access (DMA) adapter includes the DMA adapter incrementing from a sub-head pointer, a sub-tail pointer until encountering an out-of-sequence packet. The DMA adapter also consumes packets between the sub-head pointer and the sub-tail pointer including incrementing with the consumption of each packet, the sub-head pointer until determining that the sub-head pointer is equal to the sub-tail pointer. In response to determining that the sub-head pointer is equal to the sub-tail pointer, the DMA adapter determines whether the head pointer is pointing to the next in-sequence packet. If the head pointer is pointing to the next in-sequence packet, the DMA adapter resets the sub-head pointer and the sub-tail pointer to the head pointer. If the head pointer is not pointing to the next in-sequence packet, the DMA adapter resets the sub-head pointer and the sub-tail pointer to the next in-sequence packet.