Comparison of hardware and software cache coherence schemes
Sarita V. Adve, Vikram Adve, Mark D. Hill, Mary K. Vernon · 1991
We use mean value analysis models to compare representative hardware and software cache coherence schemes for a large-scale shared-memory system.Our goal is to identify the workloads for which either of the schemes is significantly better.Our methodology improves upon previous analytical studies and complements previous simulation studies by developing a common high-level workload model that is used to derive separate sets of lowlevel workload parameters for the two schemes.This approach allows an equitable comparison of the two schemes for a specific workload.Our results show that software schemes are comparable (in terms of processor efficiency) to hardware schemes for a wide class of programs.The only cases for which software schemes perform significantly worse than hardware schemes are when there is a greater than 15% reduction in hit rate due to inaccurate prediction of memory access conflicts, or when there are many writes in the program that are not executed at runtime.For relatively wellstructured and deterministic programs, on the other hand, software schemes perform significantly better than hardware schemes.