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[Bug libc/21396] Use AVX2 memcpy/memset on Skylake server
- From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sourceware dot org
- Date: Tue, 18 Apr 2017 21:02:39 +0000
- Subject: [Bug libc/21396] Use AVX2 memcpy/memset on Skylake server
- Auto-submitted: auto-generated
- References: <bug-21396-131@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=21396
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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4cb334c4d6249686653137ec273d081371b3672d
commit 4cb334c4d6249686653137ec273d081371b3672d
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Apr 18 14:01:45 2017 -0700
x86: Use AVX2 memcpy/memset on Skylake server [BZ #21396]
On Skylake server, AVX512 load/store instructions in memcpy/memset may
lead to lower CPU turbo frequency in certain situations. Use of AVX2
in memcpy/memset has been observed to have improved overall performance
in many workloads due to the higher frequency.
Since AVX512ER is unique to Xeon Phi, this patch sets Prefer_No_AVX512
if AVX512ER isn't available so that AVX2 versions of memcpy/memset are
used on Skylake server.
[BZ #21396]
* sysdeps/x86/cpu-features.c (init_cpu_features): Set
Prefer_No_AVX512 if AVX512ER isn't available.
* sysdeps/x86/cpu-features.h (bit_arch_Prefer_No_AVX512): New.
(index_arch_Prefer_No_AVX512): Likewise.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Don't use
AVX512 version if Prefer_No_AVX512 is set.
* sysdeps/x86_64/multiarch/memcpy_chk.S (__memcpy_chk):
Likewise.
* sysdeps/x86_64/multiarch/memmove.S (__libc_memmove): Likewise.
* sysdeps/x86_64/multiarch/memmove_chk.S (__memmove_chk):
Likewise.
* sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Likewise.
* sysdeps/x86_64/multiarch/mempcpy_chk.S (__mempcpy_chk):
Likewise.
* sysdeps/x86_64/multiarch/memset.S (memset): Likewise.
* sysdeps/x86_64/multiarch/memset_chk.S (__memset_chk):
Likewise.
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 21 +++++++++++++++++++++
sysdeps/x86/cpu-features.c | 6 +++++-
sysdeps/x86/cpu-features.h | 3 +++
sysdeps/x86_64/multiarch/memcpy.S | 2 ++
sysdeps/x86_64/multiarch/memcpy_chk.S | 2 ++
sysdeps/x86_64/multiarch/memmove.S | 2 ++
sysdeps/x86_64/multiarch/memmove_chk.S | 2 ++
sysdeps/x86_64/multiarch/mempcpy.S | 2 ++
sysdeps/x86_64/multiarch/mempcpy_chk.S | 2 ++
sysdeps/x86_64/multiarch/memset.S | 2 ++
sysdeps/x86_64/multiarch/memset_chk.S | 2 ++
11 files changed, 45 insertions(+), 1 deletions(-)
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