Repeated references to local variables are good because the compiler cancache them in the register file (temporal locality).. Stride-1 reference patterns are good because caches at all levels of the memoryhierarchy store data as contiguous blocks (spatial locality).

A copy of w is contained in the line if and only if the valid bit is setand the tag in the cache line matches the tag in the address of w.

The process that a cache goes through of determining whether a request is ahit or a miss and then extracting the requested word consists of three steps: (1) setselection, (2) line matching, and (3) word extraction.

a program needs a particular data object d from level k + 1, it first looksfor d in one of the blocks currently stored at level k. If d happens to be cachedat level k, then we have what is called a cache hit.