ARC often wins against LRU, but there is a lot of left on the table compared to other policies. That's because they do capture some frequency, but not very well

ARC often wins against LRU, but there is a lot of left on the table compared to other policies. That's because they do capture some frequency, but not very well imho. You can mitigate the exclusive lock using a write-ahead log approach [1] [2]. Then you record events into ring buffers, replay in batches, and have an exclusive tryLock. This works really well in practice and lets you do much more complex policy work without much less worry about concurrency. [1] http://highscalability.com/blog/2016/1/25/design-of-a-modern-cache.html http://highscalability.com/blog/2016/1/25/design-of-a-modern... [2] http://web.cse.ohio-state.edu/hpcs/WWW/HTML/publications/papers/TR-09-1.pdf http://web.cse.ohio-state.edu/hpcs/WWW/HTML/publications/pap...