From: Andrew Morton <akpm@linux-foundation.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Glauber Costa <glommer@parallels.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
Paul Tuner <pjt@google.com>
Subject: Re: [PATCH v2] proc: speedup /proc/stat handling
Date: Tue, 24 Jan 2012 17:27:32 -0800 [thread overview]
Message-ID: <20120124172732.19b3d9f4.akpm@linux-foundation.org> (raw)
In-Reply-To: <1327450945.14373.24.camel@edumazet-laptop>
On Wed, 25 Jan 2012 01:22:25 +0100
Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le mardi 24 janvier 2012 __ 16:12 -0800, Andrew Morton a __crit :
>
> > Did you measure the improvement from this patch?
>
> Unfortunately I can not reboot the server where I noticed this
> performance problem.
>
> On the smaller one, performance improvement is about 20%, because the
> second run of show_stat() can use data present in cpu cache.
>
> On big machines, I guess the 128 bytes per possible cpu reservation can
> avoid the second run. (since a typical cpuXXX line is smaller than 128
> bytes)
I had a fiddle on an 8-way x86_64 machine. I'm unable to demonstrate
any improvement for either of
time (for i in $(seq 1000); do; cat /proc/self/stat > /dev/null; done)
time (for i in $(seq 1000); do; cat /proc/1/stat > /dev/null; done)
oh well.
next prev parent reply other threads:[~2012-01-25 1:27 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-20 15:59 [PATCH] proc: speedup /proc/stat handling Eric Dumazet
2012-01-20 22:55 ` Andrew Morton
2012-01-23 10:16 ` KAMEZAWA Hiroyuki
2012-01-23 10:33 ` Glauber Costa
2012-01-24 1:25 ` KAMEZAWA Hiroyuki
2012-01-25 0:01 ` [PATCH v2] " Eric Dumazet
2012-01-25 0:12 ` Andrew Morton
2012-01-25 0:22 ` Eric Dumazet
2012-01-25 1:27 ` Andrew Morton [this message]
2012-01-25 5:29 ` Eric Dumazet
2012-01-26 1:04 ` Andrew Morton
2012-01-26 9:55 ` KAMEZAWA Hiroyuki
2012-01-27 0:43 ` Andrew Morton
2012-01-27 1:09 ` KAMEZAWA Hiroyuki
2012-01-27 1:18 ` Andrew Morton
2012-01-30 5:16 ` [PATCH] Add num_to_str() for speedup /proc/stat KAMEZAWA Hiroyuki
2012-01-30 23:20 ` Andrew Morton
2012-01-30 23:58 ` KAMEZAWA Hiroyuki
2012-02-01 14:43 ` Andrea Righi
2012-02-01 23:46 ` KAMEZAWA Hiroyuki
2012-01-27 7:09 ` [PATCH v2] proc: speedup /proc/stat handling Eric Dumazet
2012-01-25 0:18 ` KAMEZAWA Hiroyuki
2012-01-25 0:26 ` Eric Dumazet
2012-01-30 8:06 ` Jörg-Volker Peetz
2012-01-30 9:25 ` Eric Dumazet
2012-01-30 10:00 ` Jörg-Volker Peetz
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=20120124172732.19b3d9f4.akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=a.p.zijlstra@chello.nl \
--cc=eric.dumazet@gmail.com \
--cc=glommer@parallels.com \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=mingo@elte.hu \
--cc=pjt@google.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.