From f64058914af3c3a429e5947a8a90220240f7d51b Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 6 Dec 2021 07:14:12 -0800 Subject: [PATCH] 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) --- sysdeps/x86/cpu-features.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 956bfb4f..5ff2baa0 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -525,8 +525,11 @@ init_cpu_features (struct cpu_features *cpu_features) |= 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. */ -- GitLab