Method and apparatus for using a non-committing data cache to facilitate speculative execution

A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for facilitating speculative execution of instructions within a computer system, the method comprising:

• encountering a stall during execution of an instruction stream;
• and in response to the stall,
• synchronizing a cache containing data operated on by the instruction stream,
• configuring the cache so that the cache operates as before except that changes to cache lines are not propagated to lower levels of a memory system unless a subsequent commit operation takes place, and
• speculatively executing a subsequent portion of the instruction stream without waiting for an event that caused the stall to be resolved, wherein the speculative execution operates on data within the cache.

An apparatus for facilitating speculative execution of instructions within a computer system, comprising:

• a stall encountering mechanism that is configured to encounter a stall during execution of an instruction stream;
• a synchronizing mechanism that is configured to synchronize a cache containing data operated on by the instruction stream;
• a configuring mechanism that is configured to configure the cache so that the cache operates as before except that changes to cache lines are not propagated to lower levels of a memory system unless a subsequent commit operation takes place;
• and
• an executing mechanism that is configured to speculatively execute a subsequent portion of the instruction stream without waiting for an event that caused the stall to be resolved, wherein the speculative execution operates on data within the cache.