Cache performance is becoming increasingly important in modern processors. Jouppi shows how the cost of a level 1 cache miss has increased as the gap between processor speed and memory speed as widened. This trend is continuing, and memory subsytem performance is often a major bottleneck in modern computers. 1.1 Victim Caching Victim caching is a technique for reducing conflict misses in a direct mapped cache. The basic idea is to gain the advantages of a 2 or 4-way set associative cache by extending only the lines that have conflicts.
Victims are entries that are removed from the cache to make room for other entries.
Because it is not as fast as the direct-mapped cache, the victim cache is not placed in the critical path of the processor. Jouppi found that even small victim caches can be extremely effective in improving performance. In terms of performance per cache memory element, victim caches are a very good investment, assuming that Jouppi's traces are representative of the programs you run on your computer. Conventional Prefetch Stream buffers are a form of prefetching. When a cache miss occurs, prefetch on miss simply requests the next cache entry in addition to the currently referenced cache entry.