public inbox for gcc-help@gcc.gnu.org
 help / color / mirror / Atom feed
From: Satish Vasudeva <satish.vasudeva@cohesity.com>
To: gcc-help@gcc.gnu.org
Subject: Libatomic 16B
Date: Wed, 23 Feb 2022 08:42:05 -0800	[thread overview]
Message-ID: <CABp-Vv+QQCri1miq9xr0Ug_Fyb-LxBTbJR-GXDb2YgXKrA1LJA@mail.gmail.com> (raw)

Hi Team,

I was looking at the hotspots in our software stack and interestingly I see
libat_load_16_i1 seems to be one of the top in the list.

I am trying to understand why that is the case. My suspicion is some kind
of lock usage for 16B atomic accesses.

I came across this discussion but frankly I am still confused.
https://gcc.gnu.org/legacy-ml/gcc-patches/2017-01/msg02344.html

Do you think the overhead of libat_load_16_i1 is due to spinlock usage?
Also reading some other Intel CPU docs, it seems like the CPU does support
loading 16B in single access. In that case can we optimize this for
performance?

Thanks and appreciate your help.

Satish

             reply	other threads:[~2022-02-23 16:41 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-23 16:42 Satish Vasudeva [this message]
2022-02-24 16:42 ` Satish Vasudeva
2022-02-25 13:53   ` Florian Weimer
2022-02-24 19:09 ` Xi Ruoyao
2022-02-24 19:35   ` Satish Vasudeva
2022-02-24 20:05     ` Xi Ruoyao
2022-02-24 20:13       ` Segher Boessenkool
2022-02-24 20:38         ` Satish Vasudeva
2022-02-25  8:35           ` Stefan Ring
2022-02-25  8:48             ` Xi Ruoyao
2022-02-25 14:01               ` Florian Weimer
2022-02-25 14:10                 ` Alexander Monakov
2022-02-25 14:16                   ` Xi Ruoyao
2022-02-25 14:25                 ` Xi Ruoyao
2022-02-25 17:05                   ` Satish Vasudeva
2022-02-25 17:16                     ` Xi Ruoyao
2022-02-25 17:25                       ` Satish Vasudeva
2022-03-02  0:16                         ` Satish Vasudeva
2022-03-02  5:55                           ` Florian Weimer

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=CABp-Vv+QQCri1miq9xr0Ug_Fyb-LxBTbJR-GXDb2YgXKrA1LJA@mail.gmail.com \
    --to=satish.vasudeva@cohesity.com \
    --cc=gcc-help@gcc.gnu.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).