From: Noah Goldstein via Libc-alpha <libc-alpha@sourceware.org>
To: DJ Delorie <dj@redhat.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH 5/5] x86_64: Add evex optimized bcmp implementation in bcmp-evex.S
Date: Tue, 14 Sep 2021 00:55:07 -0500 [thread overview]
Message-ID: <CAFUsyfL+F-SqYo=PXjCimLUgf_U62=f_8uVY-=qh=BruNwMMNQ@mail.gmail.com> (raw)
In-Reply-To: <xnmtof4ss3.fsf@greed.delorie.com>
On Tue, Sep 14, 2021 at 12:42 AM DJ Delorie <dj@redhat.com> wrote:
> Noah Goldstein <goldstein.w.n@gmail.com> writes:
> > I'm not 100% sure what you mean? memcmp can correctly implement bcmp
> > but not the vice versa.
>
> glibc does not have a separate implementation of bcmp(). Any calls to
> bcmp() end up calling memcmp() (through that weak alias). So your patch
> is not *optimizing* bcmp, it is *adding* bcmp. The new version you are
> adding is no longer using the optimized versions of memcmp, so you'd
> have to either (1) be very careful to not introduce a performance
> regression, or (2) optimize the existing memcmp()s further instead.
>
Ah, got it.
In the first patch of the set:
[PATCH 1/5] x86_64: Add support for bcmp using sse2, sse4_1, avx2, and evex
I have some performance numbers. Seems to be an improvement for avx2/evex.
The sse2/sse4 stuff is a bit more iffy. I don't really have the hardware to
properly
test those versions.
Thank you for all the help!
next prev parent reply other threads:[~2021-09-14 5:55 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 23:05 [PATCH 1/5] x86_64: Add support for bcmp using sse2, sse4_1, avx2, and evex Noah Goldstein via Libc-alpha
2021-09-13 23:05 ` [PATCH 2/5] x86_64: Add sse2 optimized bcmp implementation in memcmp.S Noah Goldstein via Libc-alpha
2021-09-13 23:05 ` [PATCH 3/5] x86_64: Add sse4_1 optimized bcmp implementation in memcmp-sse4.S Noah Goldstein via Libc-alpha
2021-09-13 23:05 ` [PATCH 4/5] x86_64: Add avx2 optimized bcmp implementation in bcmp-avx2.S Noah Goldstein via Libc-alpha
2021-09-13 23:05 ` [PATCH 5/5] x86_64: Add evex optimized bcmp implementation in bcmp-evex.S Noah Goldstein via Libc-alpha
2021-09-14 1:18 ` Carlos O'Donell via Libc-alpha
2021-09-14 2:05 ` Noah Goldstein via Libc-alpha
2021-09-14 2:35 ` Carlos O'Donell via Libc-alpha
2021-09-14 2:55 ` DJ Delorie via Libc-alpha
2021-09-14 3:24 ` Noah Goldstein via Libc-alpha
2021-09-14 3:40 ` Noah Goldstein via Libc-alpha
2021-09-14 4:21 ` DJ Delorie via Libc-alpha
2021-09-14 5:29 ` Noah Goldstein via Libc-alpha
2021-09-14 5:42 ` DJ Delorie via Libc-alpha
2021-09-14 5:55 ` Noah Goldstein via Libc-alpha [this message]
2021-09-13 23:22 ` [PATCH 1/5] x86_64: Add support for bcmp using sse2, sse4_1, avx2, and evex Noah Goldstein via Libc-alpha
2021-09-14 6:30 ` [PATCH v2 " Noah Goldstein via Libc-alpha
2021-09-14 6:30 ` [PATCH v2 2/5] x86_64: Add sse2 optimized bcmp implementation in memcmp.S Noah Goldstein via Libc-alpha
2021-09-14 6:30 ` [PATCH v2 3/5] x86_64: Add sse4_1 optimized bcmp implementation in memcmp-sse4.S Noah Goldstein via Libc-alpha
2021-09-14 6:30 ` [PATCH v2 4/5] x86_64: Add avx2 optimized bcmp implementation in bcmp-avx2.S Noah Goldstein via Libc-alpha
2021-09-14 6:30 ` [PATCH v2 5/5] x86_64: Add evex optimized bcmp implementation in bcmp-evex.S Noah Goldstein via Libc-alpha
2021-09-14 14:40 ` [PATCH v2 1/5] x86_64: Add support for bcmp using sse2, sse4_1, avx2, and evex H.J. Lu via Libc-alpha
2021-09-14 19:23 ` Noah Goldstein via Libc-alpha
2021-09-14 20:30 ` Florian Weimer via Libc-alpha
2021-09-15 0:00 ` [PATCH " Joseph Myers
2021-09-15 13:37 ` Zack Weinberg via Libc-alpha
2021-09-15 14:01 ` Re: [PATCH 1/5] x86_64: Add support for bcmp using sse2, sse 4_1, " Florian Weimer via Libc-alpha
2021-09-15 18:06 ` Noah Goldstein via Libc-alpha
2021-09-15 18:30 ` Joseph Myers
2021-09-27 1:35 ` Noah Goldstein via Libc-alpha
2021-09-27 7:29 ` Florian Weimer via Libc-alpha
2021-09-27 16:49 ` Noah Goldstein via Libc-alpha
2021-09-27 16:54 ` Florian Weimer via Libc-alpha
2021-09-27 17:54 ` Noah Goldstein via Libc-alpha
2021-09-27 17:56 ` Florian Weimer via Libc-alpha
2021-09-27 18:05 ` Noah Goldstein via Libc-alpha
2021-09-27 18:10 ` Florian Weimer via Libc-alpha
2021-09-27 18:15 ` Noah Goldstein via Libc-alpha
2021-09-27 18:22 ` Florian Weimer via Libc-alpha
2021-09-27 18:34 ` Noah Goldstein via Libc-alpha
2021-09-27 18:56 ` Florian Weimer via Libc-alpha
2021-09-27 19:20 ` Noah Goldstein via Libc-alpha
2021-09-27 19:34 ` Florian Weimer via Libc-alpha
2021-09-27 19:43 ` Noah Goldstein via Libc-alpha
2021-09-27 19:59 ` Florian Weimer via Libc-alpha
2021-09-27 20:22 ` Noah Goldstein via Libc-alpha
2021-09-27 20:24 ` Florian Weimer via Libc-alpha
2021-09-27 20:38 ` Noah Goldstein via Libc-alpha
2021-09-28 0:07 ` Noah Goldstein via Libc-alpha
2021-09-27 17:42 ` Joseph Myers
2021-09-27 17:48 ` Noah Goldstein via Libc-alpha
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
List information: https://www.gnu.org/software/libc/involved.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAFUsyfL+F-SqYo=PXjCimLUgf_U62=f_8uVY-=qh=BruNwMMNQ@mail.gmail.com' \
--to=libc-alpha@sourceware.org \
--cc=dj@redhat.com \
--cc=goldstein.w.n@gmail.com \
/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).