Improving performance by cache driven memory management

The efficient utilization of caches is crucial for a competitive memory hierarchy. Access times required by modern processors are continuously decreasing. Direct mapped caches provide the shortest access time. Using them yields reduced hardware costs and fast memory access but implies additional misses in the cache, resulting in performance degradation. Another source of conflicts is the addressing scheme if caches are physically addressed. For such caches, memory management affects cache utilization. Enhancements in virtual memory management as presented in this paper reduce cache misses by as much as 80% for real-indexed caches. We developed three algorithms that use runtime information. All of them are suitable for direct-mapped and set associative caches. Applied to SPECint92 benchmark suite, we measured a performance improvement of 6.9% in a multiprogramming environment for a R4000 based UNIX workstation. This figure also includes the overhead caused by the more complex memory management.<>