Method and system for avoiding livelock due to writeback collisions in a non-uniform memory access system

摘要

A method for avoiding livelocks due to colliding writebacks within a NUMA computer system is disclosed. The NUMA computer system includes at least two nodes coupled to an interconnect. Each of the two nodes includes a local system memory. In response to an attempt by a processor located at a home node to access a modified cache line at a remote node via a memory request at substantially the same time when a processor located at the remote node attempts to writeback the modified cache line to the home node, the writeback is allowed to complete at the home node without retry only if the writeback is from what a coherency directory within the home node considered as an owning node of the modified cache line. The memory request is then allowed to retry and completed at the home node.