36 lines
1.3 KiB
Diff
36 lines
1.3 KiB
Diff
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From ceeffe968c01b1202e482f4855cb6baf5c6cb713 Mon Sep 17 00:00:00 2001
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From: "H.J. Lu" <hjl.tools@gmail.com>
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Date: Mon, 6 Dec 2021 07:14:12 -0800
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Subject: [PATCH] x86: Don't set Prefer_No_AVX512 for processors with AVX512
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and AVX-VNNI
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Content-type: text/plain; charset=UTF-8
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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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---
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sysdeps/x86/cpu-features.c | 7 +++++--
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1 file changed, 5 insertions(+), 2 deletions(-)
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diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
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index 956bfb4f..5ff2baa0 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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@@ -525,8 +525,11 @@ init_cpu_features (struct cpu_features *cpu_features)
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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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--
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GitLab
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