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| author | H.J. Lu <hjl.tools@gmail.com> | 2021-07-22 20:26:25 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2021-07-28 13:23:57 -0700 |
| commit | 91cc803d27bda34919717b496b53cf279e44a922 (patch) | |
| tree | 0a6d0b00a94015f1554b6de690a620600dc7513d /sysdeps/x86/sysdep.h | |
| parent | c25c32165d8b7c506442fdc0304f7a3a223e1f42 (diff) | |
| download | glibc-91cc803d27bda34919717b496b53cf279e44a922.tar.gz glibc-91cc803d27bda34919717b496b53cf279e44a922.tar.xz glibc-91cc803d27bda34919717b496b53cf279e44a922.zip | |
x86-64: Add Avoid_Short_Distance_REP_MOVSB
commit 3ec5d83d2a237d39e7fd6ef7a0bc8ac4c171a4a5
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Sat Jan 25 14:19:40 2020 -0800
x86-64: Avoid rep movsb with short distance [BZ #27130]
introduced some regressions on Intel processors without Fast Short REP
MOV (FSRM). Add Avoid_Short_Distance_REP_MOVSB to avoid rep movsb with
short distance only on Intel processors with FSRM. bench-memmove-large
on Skylake server shows that cycles of __memmove_evex_unaligned_erms
improves for the following data size:
before after Improvement
length=4127, align1=3, align2=0: 479.38 349.25 27%
length=4223, align1=9, align2=5: 405.62 333.25 18%
length=8223, align1=3, align2=0: 786.12 496.38 37%
length=8319, align1=9, align2=5: 727.50 501.38 31%
length=16415, align1=3, align2=0: 1436.88 840.00 41%
length=16511, align1=9, align2=5: 1375.50 836.38 39%
length=32799, align1=3, align2=0: 2890.00 1860.12 36%
length=32895, align1=9, align2=5: 2891.38 1931.88 33%
Diffstat (limited to 'sysdeps/x86/sysdep.h')
| -rw-r--r-- | sysdeps/x86/sysdep.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h index 51c069bfe1..cac1d762fb 100644 --- a/sysdeps/x86/sysdep.h +++ b/sysdeps/x86/sysdep.h @@ -57,6 +57,11 @@ enum cf_protection_level #define STATE_SAVE_MASK \ ((1 << 1) | (1 << 2) | (1 << 3) | (1 << 5) | (1 << 6) | (1 << 7)) +/* Constants for bits in __x86_string_control: */ + +/* Avoid short distance REP MOVSB. */ +#define X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB (1 << 0) + #ifdef __ASSEMBLER__ /* Syntactic details of assembler. */ |