Elements of Cache Design

Main elements of Cache design are

1. Cache Size : The size of the cache should be small enough so that the overall cost per bit is close to that of main memory alone and large enough so that overall access time is close to that of cache alone. Large caches tend to be slightly slower than smaller ones because of the fact that The larger the cache the larger the number of gates involved in addressing the cache.
2. Mapping Function : Direct, Associative or Set Associative.
3. Replacement Algorithm : LRU (Least recently Used), FIFO, LFU (Least Frequently Used) or some Random one.
4. Write Policy : Write Through, Write Back or Write Once.
5. Line Size
6. Number of Caches : Single or two level and Unified or split.