Out-of-order cache returns

Abstract

Techniques for allowing cache access returns out of order are disclosed. A return ordering queue exists for each of several cache access types and stores outstanding cache accesses in the order in which those accesses were made. When a cache access request for a particular type is at the head of the return ordering queue for that type and the cache access is available for return to the wavefront that made that access, the cache system returns the cache access to the wavefront. Thus, cache accesses can be returned out of order with respect to cache accesses of different types. Allowing out-of-order returns can help to improve latency, for example in the situation where a relatively low-latency access type (e.g., a read) is issued after a relatively high-latency access type (e.g., a texture sampler operation).