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| author | H.J. Lu <hjl.tools@gmail.com> | 2021-02-26 05:36:59 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2021-03-29 07:40:17 -0700 |
| commit | 1da50d4bda07f04135dca39f40e79fc9eabed1f8 (patch) | |
| tree | bf3a3ffac8850fffcb22dfb889374349f66136b1 /sysdeps/x86/cpu-tunables.c | |
| parent | 934d88d862627a0ded8955985b43f5f12aa38046 (diff) | |
| download | glibc-1da50d4bda07f04135dca39f40e79fc9eabed1f8.zip glibc-1da50d4bda07f04135dca39f40e79fc9eabed1f8.tar.gz glibc-1da50d4bda07f04135dca39f40e79fc9eabed1f8.tar.bz2 | |
x86: Set Prefer_No_VZEROUPPER and add Prefer_AVX2_STRCMP
1. Set Prefer_No_VZEROUPPER if RTM is usable to avoid RTM abort triggered
by VZEROUPPER inside a transactionally executing RTM region.
2. Since to compare 2 32-byte strings, 256-bit EVEX strcmp requires 2
loads, 3 VPCMPs and 2 KORDs while AVX2 strcmp requires 1 load, 2 VPCMPEQs,
1 VPMINU and 1 VPMOVMSKB, AVX2 strcmp is faster than EVEX strcmp. Add
Prefer_AVX2_STRCMP to prefer AVX2 strcmp family functions.
Diffstat (limited to 'sysdeps/x86/cpu-tunables.c')
| -rw-r--r-- | sysdeps/x86/cpu-tunables.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 61b05e5..00fe504 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -239,6 +239,8 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) CHECK_GLIBC_IFUNC_PREFERRED_BOTH (n, cpu_features, Fast_Copy_Backward, disable, 18); + CHECK_GLIBC_IFUNC_PREFERRED_NEED_BOTH + (n, cpu_features, Prefer_AVX2_STRCMP, AVX2, disable, 18); } break; case 19: |