ELEG 4983 Lecture Notes - Lecture 4: Cpu Cache
28 Jan 2017
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Lec 4 types of cache misses, block replacement. Compulsory miss - assumes an infinite size cache. Occur when a block is first accessed also called cold start misses. Associativity and size of cache does not affect the compulsory miss rate. Capacity miss - if cache cannot contain all blocks needed, then misses occur because blocks are discarded and then later retrieved. Some for set and the most for direct mapped. Slope of decreasing miss rate drops towards end due to the diminishing opportunities for locality in a program. 1 to 2 kb cache for a fully associative or 8-way associative. What to replace when misses occur and all blocks are full (for set associativity) New section 1 page 1 full (for set associativity) Lease recently used (lru): replace block that has not been used for longest time. First in first out (fifo): close to lru but does not rely on usage.
