commit f3a99b2216114f89b20329ae7664b764248b4bbd Author: H.J. Lu 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. */