On Mon, Aug 26, 2024 at 06:54:58PM +0000, Amonson, Paul D wrote: >> And this still shows the ~14% regression in your original post? > > At the small buffer sizes the margin of error or "noise" is larger, > 7-11%. My average could be just bad luck. It will take me a while to > re-setup for full data collection runs but I can try it again if you > like.
IMHO that would be useful to establish the current state of the patch set from a performance standpoint, especially since you've added code intended to mitigate the regression. +#define COMP_CRC32C_SMALL(crc, data, len) \ + ((crc) = pg_comp_crc32c_sse42((crc), (data), (len))) My interpretation of Andres's upthread suggestion is that we'd add the length check within the macro instead of introducing a separate one. We'd expect the compiler to optimize out comparisons for small lengths known at compile time and always call the existing implementation (which may still involve a function pointer in most cases). -- nathan
