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x86: Enable non-temporal memset tunable for AMD

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In commit 46b5e98ef6 ("x86: Add seperate non-temporal tunable for
memset") a tunable threshold for enabling non-temporal memset was added,
but only for Intel hardware.

Since that commit, new benchmark results suggest that non-temporal
memset is beneficial on AMD, as well, so allow this tunable to be set
for AMD.

See:
https://docs.google.com/spreadsheets/d/1opzukzvum4n6-RUVHTGddV6RjAEil4P2uMjjQGLbLcU/edit?usp=sharing
which has been updated to include data using different stategies for
large memset on AMD Zen2, Zen3, and Zen4.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This commit is contained in:
Joe Damato 2024-06-07 23:04:47 +00:00 • committed by Noah Goldstein
parent 5968125f55
commit bef2a827a5
1 changed files with 4 additions and 4 deletions
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8
sysdeps/x86/dl-cacheinfo.h
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@ -986,11 +986,11 @@ dl_init_cacheinfo (struct cpu_features *cpu_features)
if (CPU_FEATURE_USABLE_P (cpu_features, FSRM))
rep_movsb_threshold = 2112;
/* Non-temporal stores in memset have only been tested on Intel hardware.
Until we benchmark data on other x86 processor, disable non-temporal
stores in memset. */
/* Non-temporal stores are more performant on Intel and AMD hardware above
non_temporal_threshold. Enable this for both Intel and AMD hardware. */
unsigned long int memset_non_temporal_threshold = SIZE_MAX;
if (cpu_features->basic.kind == arch_kind_intel)
if (cpu_features->basic.kind == arch_kind_intel
|| cpu_features->basic.kind == arch_kind_amd)
memset_non_temporal_threshold = non_temporal_threshold;
/* For AMD CPUs that support ERMS (Zen3+), REP MOVSB is in a lot of