Demote instruction for relinquishing cache line ownership

摘要

A computer system processor of a multi-processor computer system having cache subsystem, executes a demote instruction to cause a cache line exclusively owned by the computer system processor to become shared or read-only in the cache subsystem.

主权项

1. A computer system for relinquishing, by a selected processor, the selected processor's own exclusive ownership of a specified cache line, the computer system comprising:
a shared cache system; and the selected processor, the selected processor being a processor of a multi-processor system, wherein the selected processor is an out-of-order processor comprising a pipeline, each processor of the multi-processor system communicatively coupled to said shared cache system, the computer system configured to perform a method comprising: executing, by the selected processor, a demote instruction of a software program, the demote instruction specifying a logical address of a specified cache line, the executing the demote instruction by the selected processor comprising: based on the demote instruction not being in an incorrectly predicted branch path of the selected processor and determining, by the computer system, that the specified cache line in the shared cache system is exclusively owned by the selected processor, relinquishing, by the computer system, the selected processor's exclusive ownership of the cache line in the shared cache system; and based on the demote instruction being in an incorrectly predicted branch path of the selected processor, not relinquishing, by the computer system, the selected processor's exclusive ownership of the cache line in the shared cache system.