Filtering out redundant software prefetch instructions

摘要

The disclosed embodiments relate to a system that selectively filters out redundant software prefetch instructions during execution of a program on a processor. During execution of the program, the system collects information associated with hit rates for individual software prefetch instructions as the individual software prefetch instructions are executed, wherein a software prefetch instruction is redundant if the software prefetch instruction accesses a cache line that has already been fetched from memory. As software prefetch instructions are encountered during execution of the program, the system selectively filters out individual software prefetch instructions that are likely to be redundant based on the collected information, so that likely redundant software prefetch instructions are not executed by the processor.

主权项

1. A method for selectively filtering out redundant software prefetch instructions during execution of a program on a processor, comprising:
during execution of the program,
collecting information associated with hit rates for individual software prefetch instructions as the individual software prefetch instructions are executed, wherein a software prefetch instruction is determined to be redundant upon determining that the software prefetch instruction accesses a cache line that has already been fetched from memory, wherein determining that the software prefetch instruction is redundant comprises determining that a redundant count associated with an entry for the software prefetch instruction in a learning table exceeds a pre-determined threshold; andas software prefetch instructions are encountered during execution of the program, selectively filtering out individual software prefetch instructions that are likely to be redundant based on the collected information, so that likely redundant software prefetch instructions are not executed by the processor.