On Mon, Mar 18, 2024 at 04:07:40PM +0000, Amonson, Paul D wrote: > Won't I still need the runtime checks? If I compile with a compiler > supporting the HW "feature" but run on HW without that feature, I will > want to avoid faults due to illegal operations. Won't that also affect > performance?
I don't think David was suggesting that we need to remove the runtime checks for AVX512. IIUC he was pointing out that most of the performance gain is from removing the function call overhead, which your v8-0002 patch already does for the proposed AVX512 code. We can apply a similar optimization for systems without AVX512 by inlining the code for pg_popcount64() and pg_popcount32(). -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
