Among these, some of the well known techniques are set associative, fully associative and direct mapping technique. It is more practical than fully associative mapping because the associative portion is limited to just a few slots that make up a set. Caches are divided into blocks, which may be of various sizes. The number of blocks per set is deter mined by the layout of the cache e. When we copy a block of data from main memory to the cache, where exactly. In a directmapped cache structure, the cache is organized into multiple sets with a single. So on a 4way set associative cache the memory cache will have 2,048 blocks containing. The set of cache lines pointed to by the set index are set associative. A cpu cache is a memory which holds the recently utilized data by the processor. Pdf cache controller for 4way setassociative cache memory. This cache is made up of sets that can fit two blocks each. Each set contains two ways or degrees of associativity.
Set associative just means that a limited number of pages can share the same tagattributes, while full associative means that a tagattribute can be stored at any location in the tlb cache. Contribute to panchalnsetcache development by creating an account on github. Setassociative cache an overview sciencedirect topics. Problem 1 a set associative cache consists of 64 lines, or slots, divided into fourline. On this configuration the memory cache is divided in several blocks sets containing n lines each. How cache memory works why cache memory works cache design basics mapping function. This system is called set associative because the cache is partitioned into distinct sets of blocks, ad each set contains a small fixed number of blocks. Higher associativity improves hit ratio but reduces cache performance. The index is now used to find the set, and the tag helps find the block within the set. When the processor attempts to read a word of memory. Cache can provide up to k hit locations within same set for kway set associativity. Contribute to panchal nsetcache development by creating an account on github. Each way consists of a data block and the valid and tag bits. Set associative mapping replacement policies write policies space overhead types of cache misses types of caches example implementations.
Check is made to determine if the word is in the cache. This paper proposes a novel idea of set associative cache address. This is far more efficient, but this can only be done for very small caches. For any given key an item can be stored in any of the slots in the set. How the cache memory works nway set associative cache. A number of standard cache addresses mapping techniques are available. A data or code block from main memory can be allocated to any of the four ways in a set without affecting program behavior. Cache memory set associative mapped cache codingfreak. A compromise is to divide the cache into sets each of which consists of n ways nway set associative.
1333 107 253 1457 1213 536 464 1314 717 742 1429 350 570 770 206 1009 333 1130 606 137 1273 879 563 315 520 301 1033 72 59 248