Early return indication for read exclusive requests in shared memory architecture

摘要

An early return indication is used to notify a first communications interface, prior to a response being received from any of a plurality of sources coupled to a second communications interface, that the return data can be used by the first communications interface when it is received thereby from a source of the return data if the source has an exclusive copy of the return data. By doing so, the first communications interface can often prepare for forwarding the return data over its associated communication link such that the data can be forwarded with little or no latency once the data is retrieved from its source, and may be able to initiate the return of data over the communication link prior to all responses being received from the other sources. The early return indication may also serves as an early coherency indication in that the first communications interface is no longer required to wait for updating of a coherency directory to complete prior to forwarding the return data over the communication link.