Message 283077 - Python tracker (original) (raw)

Technically the patch LGTM. But we should find the cause of the regression in some benchmarks.

The benchmark is on Sandy Bridge (Core i5 2400) and I didn't use PGO build. perf_event reported branch-miss rate increase at cpickle's save function.

I'll rerun benchmark with PGO build. I hope PGO is friendly with CPU branch prediction, like L1/L2 cache.

Anyway, recent amd64 CPUs have more large branch history.

And would be nice to extend the optimization to C functions. In any case this optimization is worth mentioning in What's New.

I'll do them.