⚡ BitFaster.Caching

High performance, thread-safe in-memory caching primitives for .NET.

ConcurrentLru

ConcurrentLru is a light weight drop in replacement for ConcurrentDictionary, but with bounded size enforced by the TU-Q eviction policy (based on 2Q). There are no background threads, no global locks, concurrent throughput is high, lookups are fast and hit rate outperforms a pure LRU in all tested scenarios.

Choose a capacity and use just like ConcurrentDictionary, but with bounded size:

int capacity = 128;
var lru = new ConcurrentLru<string, SomeItem>(capacity);

var value = lru.GetOrAdd("key", (key) => new SomeItem(key));

Optionally configure ConcurrentLru with a time-based eviction policy, either:

• Expire after write
• Expire after access
• Calculate an expiry time per item

ConcurrentLfu

ConcurrentLfu is a drop in replacement for ConcurrentDictionary, but with bounded size enforced by the W-TinyLFU admission policy. ConcurrentLfu has near optimal hit rate and high scalability. Reads and writes are buffered then replayed asynchronously to mitigate lock contention.

Choose a capacity and use just like ConcurrentDictionary, but with bounded size:

int capacity = 128;
var lfu = new ConcurrentLfu<string, SomeItem>(capacity);

var value = lfu.GetOrAdd("key", (key) => new SomeItem(key));

Documentation

Please refer to the wiki for full API documentation, and a complete analysis of hit rate, latency and throughput.