commit f3a99b2216114f89b20329ae7664b764248b4bbd

Author: H.J. Lu <hjl.tools@gmail.com>

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.  */