Some versions of kv95 and kv0 saw a ~10% performance regression around October 28th, e.g. kv95/enc=false/nodes=1/cpu=32:

This is even more pronounced with 64KB payloads, e.g. kv95/enc=false/nodes=3/cpu=32/size=64kb:

Admission control was enabled by default in #68535, which merged on October 28th, so that seems like a likely culprit. Running a couple of benchmarks to confirm.