public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
From: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
To: Danila Kutenin <danilak@google.com>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH] aarch64: Optimize string functions with shrn instruction
Date: Wed, 6 Jul 2022 09:30:12 +0100	[thread overview]
Message-ID: <YsVIFIQ4+lFI+dGN@arm.com> (raw)
In-Reply-To: <CA+EkT6ucwr_XqpVxzBpj1YVEMn4_kdFoZYSWDbGSruqBzAFDdA@mail.gmail.com>

The 07/06/2022 08:42, Danila Kutenin wrote:
> Friendly ping
> 
> On Mon, Jun 27, 2022 at 5:12 PM Danila Kutenin <danilak@google.com> wrote:
> 
> > We found that string functions were using AND+ADDP
> > to find the nibble/syndrome mask but there is an easier
> > opportunity through `SHRN dst.8b, src.8h, 4` (shift
> > right every 2 bytes by 4 and narrow to 1 byte) and has
> > same latency on all SIMD ARMv8 targets as ADDP. There
> > are also possible gaps for memcmp but that's for
> > another patch.
> >
> > We see 10-20% savings for small-mid size cases (<=128)
> > which are primary cases for general workloads.


thanks for the patch, committed it now.

  reply	other threads:[~2022-07-06  8:30 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-27 16:12 Danila Kutenin
2022-07-06  7:42 ` Danila Kutenin
2022-07-06  8:30   ` Szabolcs Nagy [this message]
  -- strict thread matches above, loose matches on Subject: below --
2022-06-22  7:29 Danila Kutenin
2022-06-27 16:02 ` Carlos O'Donell
2022-06-27 16:12   ` Danila Kutenin
2022-06-20 17:46 Danila Kutenin
2022-06-21  9:07 ` Szabolcs Nagy
2022-06-21  9:28   ` Danila Kutenin
2022-06-22  6:48     ` Szabolcs Nagy
2022-06-22  7:31       ` Danila Kutenin
2022-06-22  8:40         ` Szabolcs Nagy

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=YsVIFIQ4+lFI+dGN@arm.com \
    --to=szabolcs.nagy@arm.com \
    --cc=danilak@google.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).