public inbox for glibc-cvs@sourceware.org
help / color / mirror / Atom feed
* [glibc/release/2.34/master] x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNI
@ 2022-04-27 2:01 Sunil Pandey
0 siblings, 0 replies; only message in thread
From: Sunil Pandey @ 2022-04-27 2:01 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f3a99b2216114f89b20329ae7664b764248b4bbd
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:
---
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 f4d4049e39..09590d8794 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. */
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2022-04-27 2:01 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-27 2:01 [glibc/release/2.34/master] x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNI Sunil Pandey
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).