IO-Uring Archive on lore.kernel.org
 help / color / Atom feed
From: Jens Axboe <axboe@kernel.dk>
To: Pavel Begunkov <asml.silence@gmail.com>,
	io-uring@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] task_put batching
Date: Sat, 18 Jul 2020 08:37:04 -0600
Message-ID: <cf209c59-547e-0a69-244d-7c1fec00a978@kernel.dk> (raw)
In-Reply-To: <cover.1595021626.git.asml.silence@gmail.com>

On 7/18/20 2:32 AM, Pavel Begunkov wrote:
> For my a bit exaggerated test case perf continues to show high CPU
> cosumption by io_dismantle(), and so calling it io_iopoll_complete().
> Even though the patch doesn't yield throughput increase for my setup,
> probably because the effect is hidden behind polling, but it definitely
> improves relative percentage. And the difference should only grow with
> increasing number of CPUs. Another reason to have this is that atomics
> may affect other parallel tasks (e.g. which doesn't use io_uring)
> 
> before:
> io_iopoll_complete: 5.29%
> io_dismantle_req:   2.16%
> 
> after:
> io_iopoll_complete: 3.39%
> io_dismantle_req:   0.465%

Still not seeing a win here, but it's clean and it _should_ work. For
some reason I end up getting the offset in task ref put growing the
fput_many(). Which doesn't (on the surface) make a lot of sense, but
may just mean that we have some weird side effects.

I have applied it, thanks.

-- 
Jens Axboe


  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-18  8:32 Pavel Begunkov
2020-07-18  8:32 ` [PATCH 1/2] tasks: add put_task_struct_many() Pavel Begunkov
2020-07-18  8:32 ` [PATCH 2/2] io_uring: batch put_task_struct() Pavel Begunkov
2020-07-18 14:37 ` Jens Axboe [this message]
2020-07-19 11:15   ` [PATCH 0/2] task_put batching Pavel Begunkov
2020-07-19 18:49     ` Jens Axboe
2020-07-20 14:18       ` Pavel Begunkov
2020-07-20 15:22   ` Pavel Begunkov
2020-07-20 15:49     ` Jens Axboe
2020-07-20 16:06       ` Pavel Begunkov
2020-07-20 16:11         ` Jens Axboe
2020-07-20 16:42           ` Pavel Begunkov

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=cf209c59-547e-0a69-244d-7c1fec00a978@kernel.dk \
    --to=axboe@kernel.dk \
    --cc=asml.silence@gmail.com \
    --cc=io-uring@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.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

IO-Uring Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/io-uring/0 io-uring/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 io-uring io-uring/ https://lore.kernel.org/io-uring \
		io-uring@vger.kernel.org
	public-inbox-index io-uring

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.io-uring


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git