Prefetch protocol for transactional memory

A method to enable a prefetch request to be controlled in response to conditions in a receiver of the prefetch request and to conditions in a source of the prefetch request, the method comprising:

• identifying, by one or more processors, based on a prefetch tag, a prefetch request that is associated with a prefetch instruction that is executed by a remote processor;
• determining, by the one or more processors, a priority for processing the prefetch request based, at least in part, on a prefetch request information included in the prefetch request, wherein the prefetch request information indicates a priority associated with the source of the prefetch request;
• determining whether the prefetch request conflicts with a memory access associated with an atomic transaction;
• generating, by the one or more processors, the prefetch request in a remote processor based on:
• (i) whether the prefetch request conflicts with the memory access associated with the atomic transaction, (ii) according to a prefetch protocol, wherein the prefetch request includes (a) a description of at least one prefetch request operation and (b) the prefetch request information, and (iii) a comparison of the priority for processing the prefetch request to a priority associated with the atomic transaction;
• and
• receiving, by a local processor of the one or more processors, the prefetch request from the remote processor.