cachesize

Cachesize is the capacity of a cache, a small, fast storage layer that holds recently accessed data to speed up future requests. In computer systems, caches sit between the processor and main memory to reduce average access time by exploiting temporal and spatial locality. The cachesize is the maximum amount of data that can be stored in the cache at once, and is usually expressed in bytes or in kilobytes, megabytes, etc.

Caches are organized by lines (blocks) of fixed size, and by sets with a given associativity (for example, direct-mapped or 2-way). When the processor requests data, it checks the cache for a hit; if the data is not present, a miss occurs and data is fetched from a lower level of the memory hierarchy. The combination of cachesize, line size, and associativity determines the cache’s hit rate and latency.

Modern CPUs typically feature multiple levels of cache. Per-core L1 caches are commonly in the range of 16–64 KB, L2 caches around 128 KB to 1 MB, and L3 caches shared among cores ranging from a few MB to tens of MB. These values vary by architecture and model and may be configurable in some systems.

In software, cachesize often denotes the maximum memory allotted for a cache used by an application or library. It helps control eviction behavior and memory pressure. A cachesize that is too small increases misses and slows performance; one that is too large can waste memory or cause contention. Cache performance also depends on eviction policies and workload characteristics.