On Fri, 1 Nov 2024 at 20:49, Michael Paquier <mich...@paquier.xyz> wrote: > > On Fri, Nov 01, 2024 at 07:44:22AM +0000, Bertrand Drouvot wrote: > > Worth to add a comment as to why pg_memory_is_all_zeros() should not > > be used here? > > I would not add one in bufpage.c, documenting that where > pg_memory_is_all_zeros() is defined may be more adapted.
The thought of having to write a comment to warn people not to use it for performance-critical things makes me think it might be better just to write a more optimal version of the function so we don't need to warn people. I looked around at the callers of the function I saw the following numbers of bytes being used for the length: 8192 (the one in question), 88, 32 and 112. I don't know how performance-critical the final three of those are, but I imagine all apart from the 32-byte one might be better with a non-inlined and more optimised version of the function. The problem with inlining the optimised version is that it's more code to inline. I've attached what I thought a more optimal version might look like in case anyone thinks making it better is a good idea. David
pg_memory_is_all_zeros_speedup.patch
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