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| author | H.J. Lu <hjl.tools@gmail.com> | 2021-12-06 07:14:12 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2021-12-06 07:14:12 -0800 |
| commit | ceeffe968c01b1202e482f4855cb6baf5c6cb713 (patch) | |
| tree | b1b4c21d343a2a9511a630568f30ea18e8aa3b33 | |
| parent | a329f68f2ef0db37cb39d6fa6de487b005feee40 (diff) | |
| download | glibc-ceeffe968c01b1202e482f4855cb6baf5c6cb713.zip glibc-ceeffe968c01b1202e482f4855cb6baf5c6cb713.tar.gz glibc-ceeffe968c01b1202e482f4855cb6baf5c6cb713.tar.bz2 | |
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.
| -rw-r--r-- | sysdeps/x86/cpu-features.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index be2498b..311ade1 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -538,8 +538,11 @@ 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. */ |