From: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
To: Noah Goldstein <goldstein.w.n@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH v3 3/7] stdlib: Optimization qsort{_r} swap implementation (BZ #19305)
Date: Fri, 15 Oct 2021 14:56:19 -0300 [thread overview]
Message-ID: <d06f9d73-6c34-859d-36f5-1cb620808a2a@linaro.org> (raw)
In-Reply-To: <CAFUsyfK8LLTuXNa5B74VGScYLMLBKb++LEimxKXNdJsxxCwqvg@mail.gmail.com>
On 15/10/2021 14:45, Noah Goldstein wrote:
> swap is in the inner loop. Seems like a pretty critical component to have fully
> optimized. The aarch64 version looks good, but the x86_64 version seems
> to be lacking. Not arguing for an arch specific version, but if the directives
> can add value to x86_64 without detracting from aarch64 seems like a zero
> cost improvement.
>
> Since size is non-constant for the tail I don't see how we are going
> avoid 3x memcpy calls. Although that can be another patch if it
> gets values.
>
>>
>>
>> [1] https://godbolt.org/z/v7e4xxqGa
Maybe use a byte copy in the tail to avoid memcpy [1], another option
might to tune SWAP_GENERIC_SIZE to make the tail less costly (16 should
be ok for most architecture, although some might be better with large
values).
[1] https://godbolt.org/z/G76dcej16
next prev parent reply other threads:[~2021-10-15 17:56 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-03 17:11 [PATCH v3 0/7] Use introsort for qsort Adhemerval Zanella via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 1/7] benchtests: Add bench-qsort Adhemerval Zanella via Libc-alpha
2021-09-04 9:09 ` Alexander Monakov via Libc-alpha
2021-09-06 18:30 ` Adhemerval Zanella via Libc-alpha
2021-10-13 3:19 ` Noah Goldstein via Libc-alpha
2021-10-15 12:52 ` Adhemerval Zanella via Libc-alpha
2021-10-15 16:39 ` Noah Goldstein via Libc-alpha
2021-10-15 17:19 ` Adhemerval Zanella via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 2/7] support: Fix getopt_long with CMDLINE_OPTIONS Adhemerval Zanella via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 3/7] stdlib: Optimization qsort{_r} swap implementation (BZ #19305) Adhemerval Zanella via Libc-alpha
2021-10-13 3:29 ` Noah Goldstein via Libc-alpha
2021-10-13 3:39 ` Noah Goldstein via Libc-alpha
2021-10-15 13:29 ` Adhemerval Zanella via Libc-alpha
2021-10-15 17:17 ` Noah Goldstein via Libc-alpha
2021-10-15 17:34 ` Adhemerval Zanella via Libc-alpha
2021-10-15 17:45 ` Noah Goldstein via Libc-alpha
2021-10-15 17:56 ` Adhemerval Zanella via Libc-alpha [this message]
2021-10-15 13:12 ` Adhemerval Zanella via Libc-alpha
2021-10-15 16:45 ` Noah Goldstein via Libc-alpha
2021-10-15 17:21 ` Adhemerval Zanella via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 4/7] stdlib: Move insertion sort out qsort Adhemerval Zanella via Libc-alpha
2021-09-06 20:35 ` Fangrui Song via Libc-alpha
2021-09-06 20:48 ` Fangrui Song via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 5/7] stdlib: qsort: Move some macros to inline function Adhemerval Zanella via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 6/7] stdlib: Implement introsort with qsort Adhemerval Zanella via Libc-alpha
2021-09-04 9:17 ` Alexander Monakov via Libc-alpha
2021-09-06 18:43 ` Adhemerval Zanella via Libc-alpha
2021-09-06 20:23 ` Fangrui Song via Libc-alpha
2021-10-13 3:53 ` Noah Goldstein via Libc-alpha
2021-09-03 17:11 ` [PATCH v3 7/7] stdlib: Remove use of mergesort on qsort (BZ #21719) Adhemerval Zanella via Libc-alpha
2021-09-03 19:18 ` [PATCH v3 0/7] Use introsort for qsort Paul Eggert
2021-09-06 14:13 ` Carlos O'Donell via Libc-alpha
2021-09-06 17:03 ` Zack Weinberg via Libc-alpha
2021-09-06 18:19 ` Adhemerval Zanella via Libc-alpha
2021-09-07 0:14 ` Paul Eggert
2021-09-07 14:32 ` Adhemerval Zanella via Libc-alpha
2021-09-07 17:39 ` Paul Eggert
2021-09-07 18:07 ` Adhemerval Zanella via Libc-alpha
2021-09-07 19:28 ` Paul Eggert
2021-09-08 11:56 ` Adhemerval Zanella via Libc-alpha
2021-09-09 0:39 ` Paul Eggert
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=d06f9d73-6c34-859d-36f5-1cb620808a2a@linaro.org \
--to=libc-alpha@sourceware.org \
--cc=adhemerval.zanella@linaro.org \
--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).