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