Comprehensive Hardware and Software Support for Operating Systems to Exploit

ÐHigh-performance multiprocessor workstations are becoming increasingly popular. Since many of the workloads running on these machines are operating-system intensive, we are interested in exploring the types of support for the operating system that the memory hierarchy of these machines should provide. In this paper, we evaluate a comprehensive set of hardware and software supports that minimize the performance losses for the operating system in a sophisticated cache hierarchy. These supports, selected from recent papers, are code layout optimization, guarded sequential instruction prefetching, instruction stream buffers, support for block operations, support for coherence activity, and software data prefetching. We evaluate these supports under a simulated environment. We show that they have a largely complementary impact and that, when combined, speed up the operating system by an average of 40 percent. Finally, a cost-performance comparison of these schemes suggests that the most cost-effective ones are code layout optimization and block operation support, while the least cost-effective one is software data prefetching. Index TermsÐCache hierarchies, shared-memory multiprocessors, architectural support for operating system, prefetching, tracedriven simulations, performance, block operations.