Virtual channels and corresponding buffer allocations for deadlock-free computer system operation

Abstract

A computer system employs virtual channels and allocates different resources to the virtual channels. Packets which do not have logical/protocol-related conflicts are grouped into a virtual channel. Accordingly, logical conflicts occur between packets in separate virtual channels. The packets within a virtual channel may share resources (and hence experience resource conflicts), but the packets within different virtual channels may not share resources. Since packets which may experience resource conflicts do not experience logical conflicts, and since packets which may experience logical conflicts do not experience resource conflicts, deadlock-free operation may be achieved. Additionally, each virtual channel may be assigned control packet buffers and data packet buffers. Control packets may be substantially smaller in size, and may occur more frequently than data packets. By providing separate buffers, buffer space may be used efficiently. If a control packet which does not specify a data packet is received, no data packet buffer space is allocated. If a control packet which does specify a data packet is received, both control packet buffer space and data packet buffer space is allocated.