Here RE2 does not fall back to the NFA, it just resets the Lazy DFA cache and starts growing it again. The latency spikes I was mentioning are due to the cost of destroying the cache (involving deallocations, pointer chasing, ...)
I'm not sure if it's with both RE2 or Rust, but some internal engines of Rust appear to allocate a fixed buffer that it constantly re-creates states into.
I'm not really familiar with the eviction technique of RE2 but I've done a lot of benchmark comparisons. A good way to really stress test RE2 is large Unicode classes, \w and \d in RE2 are ascii-only, i've noticed Unicode (\p{class}) classes very drastically change the throughput of the engine.
I'm not sure if it's with both RE2 or Rust, but some internal engines of Rust appear to allocate a fixed buffer that it constantly re-creates states into.
I'm not really familiar with the eviction technique of RE2 but I've done a lot of benchmark comparisons. A good way to really stress test RE2 is large Unicode classes, \w and \d in RE2 are ascii-only, i've noticed Unicode (\p{class}) classes very drastically change the throughput of the engine.