glibc/SOURCES/glibc-upstream-2.34-185.patch

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2022-09-27 14:07:57 +00:00
commit f3a99b2216114f89b20329ae7664b764248b4bbd
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Mon Dec 6 07:14:12 2021 -0800
x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNI
Don't set Prefer_No_AVX512 on processors with AVX512 and AVX-VNNI since
they won't lower CPU frequency when ZMM load and store instructions are
used.
(cherry picked from commit ceeffe968c01b1202e482f4855cb6baf5c6cb713)
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index f4d4049e391cbabd..09590d8794b1c6fb 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -566,8 +566,11 @@ disable_tsx:
|= bit_arch_Prefer_No_VZEROUPPER;
else
{
- cpu_features->preferred[index_arch_Prefer_No_AVX512]
- |= bit_arch_Prefer_No_AVX512;
+ /* Processors with AVX512 and AVX-VNNI won't lower CPU frequency
+ when ZMM load and store instructions are used. */
+ if (!CPU_FEATURES_CPU_P (cpu_features, AVX_VNNI))
+ cpu_features->preferred[index_arch_Prefer_No_AVX512]
+ |= bit_arch_Prefer_No_AVX512;
/* Avoid RTM abort triggered by VZEROUPPER inside a
transactionally executing RTM region. */