1// Package lru provides three different LRU caches of varying sophistication.
 2//
 3// Cache is a simple LRU cache. It is based on the
 4// LRU implementation in groupcache:
 5// https://github.com/golang/groupcache/tree/master/lru
 6//
 7// TwoQueueCache tracks frequently used and recently used entries separately.
 8// This avoids a burst of accesses from taking out frequently used entries,
 9// at the cost of about 2x computational overhead and some extra bookkeeping.
10//
11// ARCCache is an adaptive replacement cache. It tracks recent evictions as
12// well as recent usage in both the frequent and recent caches. Its
13// computational overhead is comparable to TwoQueueCache, but the memory
14// overhead is linear with the size of the cache.
15//
16// ARC has been patented by IBM, so do not use it if that is problematic for
17// your program.
18//
19// All caches in this package take locks while operating, and are therefore
20// thread-safe for consumers.
21package lru