| commit | 41c51f0c68b21b4603bd2a9c3d3ad017fdd22627 | |
| author | Nathan Bossart <nathan@postgresql.org> | |
| Sun, 7 Apr 2024 03:58:23 +0000 (6 22:58 -0500) | ||
| committer | Nathan Bossart <nathan@postgresql.org> | |
| Sun, 7 Apr 2024 03:58:23 +0000 (6 22:58 -0500) | ||
| tree | 2dbdd46a201de8197c39d51edb91dec39e28420d | treesnapshot (tar.gz zip) |
| parent | 792752af4eb5cf7b5b8b0470dbf22901c5178fe5 | commitdiff |
Optimize visibilitymap_count() with AVX-512 instructions.
Commit 792752af4e added infrastructure for using AVX-512 intrinsic
functions, and this commit uses that infrastructure to optimize
visibilitymap_count(). Specificially, a new pg_popcount_masked()
function is introduced that applies a bitmask to every byte in the
buffer prior to calculating the population count, which is used to
filter out the all-visible or all-frozen bits as needed. Platforms
without AVX-512 support should also see a nice speedup due to the
reduced number of calls to a function pointer.
Co-authored-by: Ants Aasma
Discussion: https://postgr.es/m/BL1PR11MB5304097DF7EA81D04C33F3D1DCA6A%40BL1PR11MB5304.namprd11.prod.outlook.com
Commit 792752af4e added infrastructure for using AVX-512 intrinsic
functions, and this commit uses that infrastructure to optimize
visibilitymap_count(). Specificially, a new pg_popcount_masked()
function is introduced that applies a bitmask to every byte in the
buffer prior to calculating the population count, which is used to
filter out the all-visible or all-frozen bits as needed. Platforms
without AVX-512 support should also see a nice speedup due to the
reduced number of calls to a function pointer.
Co-authored-by: Ants Aasma
Discussion: https://postgr.es/m/BL1PR11MB5304097DF7EA81D04C33F3D1DCA6A%40BL1PR11MB5304.namprd11.prod.outlook.com