From: "H.J. Lu" <hjl.tools@gmail.com>
To: Noah Goldstein <goldstein.w.n@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: [PATCH v2] x86: Set rep_movsb_threshold to 2112 on processors with FSRM
Date: Sat, 1 May 2021 07:08:46 -0700 [thread overview]
Message-ID: <CAMe9rOr1Sjcsuh1WdoDGNf5rFCK61B7aTAgTzsyA81vep2Khwg@mail.gmail.com> (raw)
In-Reply-To: <CAMe9rOpRHGYJ=9-WCONL-YxcaVEGcR7jRQTRUPTpQRRv6bKZOQ@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 11985 bytes --]
On Fri, Apr 30, 2021 at 6:26 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Apr 30, 2021 at 5:17 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > On Fri, Apr 30, 2021 at 4:51 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > >
> > > On Fri, Apr 30, 2021 at 3:59 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > > >
> > > > On Fri, Apr 30, 2021 at 4:43 PM H.J. Lu via Libc-alpha
> > > > <libc-alpha@sourceware.org> wrote:
> > > > >
> > > > > The glibc memcpy benchmark on Intel Core i7-1065G7 (Ice Lake) showed
> > > > > that REP MOVSB became faster after 2112 bytes:
> > > > >
> > > > > Vector + REP MOVSB REP MOVSB
> > > > > length=2112, align1=0, align2=0: 24.20 24.40
> > > > > length=2112, align1=1, align2=0: 26.07 23.13
> > > > > length=2112, align1=0, align2=1: 27.18 28.13
> > > > > length=2112, align1=1, align2=1: 26.23 25.16
> > > > > length=2176, align1=0, align2=0: 23.18 22.52
> > > > > length=2176, align1=2, align2=0: 25.45 22.52
> > > > > length=2176, align1=0, align2=2: 27.14 27.82
> > > > > length=2176, align1=2, align2=2: 22.73 25.56
> > > > > length=2240, align1=0, align2=0: 24.62 24.25
> > > > > length=2240, align1=3, align2=0: 29.77 27.15
> > > > > length=2240, align1=0, align2=3: 35.55 29.93
> > > > > length=2240, align1=3, align2=3: 34.49 25.15
> > > > > length=2304, align1=0, align2=0: 34.75 26.64
> > > > > length=2304, align1=4, align2=0: 32.09 22.63
> > > > > length=2304, align1=0, align2=4: 28.43 31.24
> > > > >
> > > >
> > > > Do you know what is happening at:
> > > > length=2304, align1=0, align2=4: 28.43 31.24
> > > >
> > > > Seems align2 > align1 gets worse for larger sizes as well.
> > > >
> > > > I.e from my Icelake (1 run):
> > > > w/o
> > > > Patch w/ Patch
> > > > length=3648, align1=0, align2=25: 72.91 83.99
> > > > length=3712, align1=0, align2=26: 72.52 84.92
> > > > length=3776, align1=0, align2=27: 76.16 84.02
> > > > length=3840, align1=0, align2=28: 75.44 90.13
> > > > length=3904, align1=0, align2=29: 81.62 84.43
> > > > length=3968, align1=0, align2=30: 76.82 93.39
> > > > length=4032, align1=0, align2=31: 80.01 89.89
> > > > length=4096, align1=0, align2=32: 72.89 97.50
> > >
> > > On Intel Core i7-1165G7 (Tiger Lake), I got
> >
> > Where the original numbers icl or tgl? But was just wondering
>
> Here are numbers on Core i7-1065G7 (Ice Lake):
>
> __memcpy_evex_unaligned_erms __memcpy_erms
> length=2048, align1=0, align2=0: 21.51 22.52
> length=2048, align1=0, align2=0: 22.11 21.50
> length=2048, align1=0, align2=0: 21.96 22.10
> length=2048, align1=0, align2=0: 22.58 21.51
> length=2112, align1=0, align2=0: 24.20 24.40
> length=2112, align1=1, align2=0: 26.07 23.13
> length=2112, align1=0, align2=1: 27.18 28.13
> length=2112, align1=1, align2=1: 26.23 25.16
> length=2176, align1=0, align2=0: 23.18 22.52
> length=2176, align1=2, align2=0: 25.45 22.52
> length=2176, align1=0, align2=2: 27.14 35.82
> length=2176, align1=2, align2=2: 22.73 25.56
> length=2240, align1=0, align2=0: 24.62 24.25
> length=2240, align1=3, align2=0: 29.77 27.15
> length=2240, align1=0, align2=3: 35.55 29.93
> length=2240, align1=3, align2=3: 34.49 25.15
> length=2304, align1=0, align2=0: 34.75 26.64
> length=2304, align1=4, align2=0: 32.09 22.63
> length=2304, align1=0, align2=4: 28.43 31.24
> length=2304, align1=4, align2=4: 23.95 25.56
> length=2368, align1=0, align2=0: 25.57 24.34
> length=2368, align1=5, align2=0: 30.57 23.94
> length=2368, align1=0, align2=5: 31.29 31.24
> length=2368, align1=5, align2=5: 25.57 26.69
> length=2432, align1=0, align2=0: 25.16 23.77
> length=2432, align1=6, align2=0: 29.27 23.13
> length=2432, align1=0, align2=6: 30.40 33.77
> length=2432, align1=6, align2=6: 25.16 26.37
> length=2496, align1=0, align2=0: 26.85 24.34
> length=2496, align1=7, align2=0: 32.04 24.75
> length=2496, align1=0, align2=7: 32.70 33.06
> length=2496, align1=7, align2=7: 26.79 25.97
> length=2560, align1=0, align2=0: 61.84 23.53
> length=2560, align1=8, align2=0: 30.74 23.53
> length=2560, align1=0, align2=8: 33.35 35.44
> length=2560, align1=8, align2=8: 27.94 27.52
> length=2624, align1=0, align2=0: 27.60 24.75
> length=2624, align1=9, align2=0: 33.28 25.16
> length=2624, align1=0, align2=9: 34.14 34.48
> length=2624, align1=9, align2=9: 28.00 26.78
> length=2688, align1=0, align2=0: 38.94 24.61
> length=2688, align1=10, align2=0: 31.23 23.94
> length=2688, align1=0, align2=10: 33.89 37.11
> length=2688, align1=10, align2=10: 28.40 27.18
> length=2752, align1=0, align2=0: 36.17 25.56
> length=2752, align1=11, align2=0: 35.88 25.57
> length=2752, align1=0, align2=11: 35.40 36.11
> length=2752, align1=11, align2=11: 28.82 27.94
> length=2816, align1=0, align2=0: 33.78 24.54
> length=2816, align1=12, align2=0: 33.75 25.96
> length=2816, align1=0, align2=12: 34.24 37.73
> length=2816, align1=12, align2=12: 29.22 27.59
> length=2880, align1=0, align2=0: 39.76 25.97
> length=2880, align1=13, align2=0: 41.26 26.66
> length=2880, align1=0, align2=13: 40.72 37.73
> length=2880, align1=13, align2=13: 35.13 27.59
> length=2944, align1=0, align2=0: 32.09 24.75
> length=2944, align1=14, align2=0: 40.27 26.78
> length=2944, align1=0, align2=14: 45.59 39.55
> length=2944, align1=14, align2=14: 40.94 28.00
> length=3008, align1=0, align2=0: 42.17 25.97
> length=3008, align1=15, align2=0: 41.81 27.07
> length=3008, align1=0, align2=15: 42.67 39.35
> length=3008, align1=15, align2=15: 42.18 28.00
> length=3072, align1=0, align2=0: 34.71 25.16
> length=3072, align1=16, align2=0: 43.31 26.37
> length=3072, align1=0, align2=16: 43.41 40.98
> length=3072, align1=16, align2=16: 36.62 27.99
> length=3136, align1=0, align2=0: 45.75 26.78
> length=3136, align1=17, align2=0: 43.29 27.59
> length=3136, align1=0, align2=17: 44.44 41.16
> length=3136, align1=17, align2=17: 34.99 28.59
> length=3200, align1=0, align2=0: 43.12 25.16
> length=3200, align1=18, align2=0: 43.04 27.59
> length=3200, align1=0, align2=18: 45.08 42.59
> length=3200, align1=18, align2=18: 36.00 28.81
> length=3264, align1=0, align2=0: 43.01 27.48
> length=3264, align1=19, align2=0: 47.72 28.61
> length=3264, align1=0, align2=19: 47.00 42.60
> length=3264, align1=19, align2=19: 44.44 28.81
> length=3328, align1=0, align2=0: 35.50 25.75
> length=3328, align1=20, align2=0: 44.84 27.19
> length=3328, align1=0, align2=20: 46.38 44.41
> length=3328, align1=20, align2=20: 33.68 28.81
> length=3392, align1=0, align2=0: 43.82 27.18
> length=3392, align1=21, align2=0: 45.91 28.81
> length=3392, align1=0, align2=21: 47.61 43.06
> length=3392, align1=21, align2=21: 43.82 29.21
> length=3456, align1=0, align2=0: 43.83 26.64
> length=3456, align1=22, align2=0: 44.77 29.49
> length=3456, align1=0, align2=22: 47.57 46.01
> length=3456, align1=22, align2=22: 44.11 29.62
> length=3520, align1=0, align2=0: 45.04 27.99
> length=3520, align1=23, align2=0: 46.59 30.55
> length=3520, align1=0, align2=23: 50.58 44.80
> length=3520, align1=23, align2=23: 43.85 29.21
> length=3584, align1=0, align2=0: 45.04 26.88
> length=3584, align1=24, align2=0: 47.22 29.21
> length=3584, align1=0, align2=24: 50.12 47.47
> length=3584, align1=24, align2=24: 45.04 29.80
> length=3648, align1=0, align2=0: 47.13 28.40
> length=3648, align1=25, align2=0: 48.78 30.94
> length=3648, align1=0, align2=25: 49.25 61.42
> length=3648, align1=25, align2=25: 45.85 30.02
> length=3712, align1=0, align2=0: 47.24 27.19
> length=3712, align1=26, align2=0: 48.41 30.79
> length=3712, align1=0, align2=26: 49.65 51.57
> length=3712, align1=26, align2=26: 48.76 30.33
> length=3776, align1=0, align2=0: 47.35 34.61
> length=3776, align1=27, align2=0: 49.16 31.99
> length=3776, align1=0, align2=27: 52.06 49.38
> length=3776, align1=27, align2=27: 47.36 30.43
> length=3840, align1=0, align2=0: 49.70 28.35
> length=3840, align1=28, align2=0: 50.29 31.81
> length=3840, align1=0, align2=28: 51.15 50.71
> length=3840, align1=28, align2=28: 47.07 31.65
> length=3904, align1=0, align2=0: 48.28 29.21
> length=3904, align1=29, align2=0: 51.96 32.99
> length=3904, align1=0, align2=29: 53.24 50.71
> length=3904, align1=29, align2=29: 47.88 31.64
> length=3968, align1=0, align2=0: 47.89 29.19
> length=3968, align1=30, align2=0: 51.52 32.57
> length=3968, align1=0, align2=30: 54.03 52.33
> length=3968, align1=30, align2=30: 46.62 33.15
> length=4032, align1=0, align2=0: 49.77 29.62
> length=4032, align1=31, align2=0: 53.62 34.27
> length=4032, align1=0, align2=31: 56.44 52.33
> length=4032, align1=31, align2=31: 48.94 33.16
> length=4096, align1=0, align2=0: 49.37 29.21
> length=4096, align1=32, align2=0: 50.46 33.00
> length=4096, align1=0, align2=32: 49.31 55.14
> length=4096, align1=32, align2=32: 49.28 33.05
>
> > if the align2 != 0, align1 = 0 case on Icelake warranted more investigation.
> > That being said the change is a clear winner on Icelake as well
> > for any other alignment schema.
>
> True, REP MOVSB is more efficient.
>
This is the v2 patch I am checking in next week.
Thanks.
--
H.J.
[-- Attachment #2: v2-0001-x86-Set-rep_movsb_threshold-to-2112-on-processors.patch --]
[-- Type: text/x-patch, Size: 2311 bytes --]
From e269371e0f8b8426c4880dd4991e527c03d3a735 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 30 Apr 2021 05:58:59 -0700
Subject: [PATCH v2] x86: Set rep_movsb_threshold to 2112 on processors with
FSRM
The glibc memcpy benchmark on Intel Core i7-1065G7 (Ice Lake) showed
that REP MOVSB became faster after 2112 bytes:
Vector Move REP MOVSB
length=2112, align1=0, align2=0: 24.20 24.40
length=2112, align1=1, align2=0: 26.07 23.13
length=2112, align1=0, align2=1: 27.18 28.13
length=2112, align1=1, align2=1: 26.23 25.16
length=2176, align1=0, align2=0: 23.18 22.52
length=2176, align1=2, align2=0: 25.45 22.52
length=2176, align1=0, align2=2: 27.14 27.82
length=2176, align1=2, align2=2: 22.73 25.56
length=2240, align1=0, align2=0: 24.62 24.25
length=2240, align1=3, align2=0: 29.77 27.15
length=2240, align1=0, align2=3: 35.55 29.93
length=2240, align1=3, align2=3: 34.49 25.15
length=2304, align1=0, align2=0: 34.75 26.64
length=2304, align1=4, align2=0: 32.09 22.63
length=2304, align1=0, align2=4: 28.43 31.24
Use REP MOVSB for data size > 2112 bytes in memcpy on processors with
fast short REP MOVSB (FSRM).
* sysdeps/x86/dl-cacheinfo.h (dl_init_cacheinfo): Set
rep_movsb_threshold to 2112 on processors with fast short REP
MOVSB (FSRM).
---
sysdeps/x86/dl-cacheinfo.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/sysdeps/x86/dl-cacheinfo.h b/sysdeps/x86/dl-cacheinfo.h
index d9944250fc..e6c94dfd02 100644
--- a/sysdeps/x86/dl-cacheinfo.h
+++ b/sysdeps/x86/dl-cacheinfo.h
@@ -891,6 +891,10 @@ dl_init_cacheinfo (struct cpu_features *cpu_features)
minimum_rep_movsb_threshold = 16 * 8;
#endif
}
+ /* NB: The default REP MOVSB threshold is 2112 on processors with fast
+ short REP MOVSB (FSRM). */
+ if (CPU_FEATURE_USABLE_P (cpu_features, FSRM))
+ rep_movsb_threshold = 2112;
unsigned long int rep_movsb_stop_threshold;
/* ERMS feature is implemented from AMD Zen3 architecture and it is
--
2.31.1
next prev parent reply other threads:[~2021-05-01 14:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-30 18:24 [PATCH] " H.J. Lu
2021-04-30 22:59 ` Noah Goldstein
2021-04-30 23:50 ` H.J. Lu
2021-05-01 0:17 ` Noah Goldstein
2021-05-01 1:26 ` H.J. Lu
2021-05-01 14:08 ` H.J. Lu [this message]
2021-05-01 18:45 ` [PATCH v2] " Noah Goldstein
2022-04-27 23:56 ` Sunil Pandey
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAMe9rOr1Sjcsuh1WdoDGNf5rFCK61B7aTAgTzsyA81vep2Khwg@mail.gmail.com \
--to=hjl.tools@gmail.com \
--cc=goldstein.w.n@gmail.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).