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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.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] Add num_to_str() for speedup /proc/stat
Date: Tue, 31 Jan 2012 08:58:20 +0900	[thread overview]
Message-ID: <20120131085820.cba068d6.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <20120130152051.89024fba.akpm@linux-foundation.org>

On Mon, 30 Jan 2012 15:20:51 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:

> On Mon, 30 Jan 2012 14:16:19 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> 
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> > Date: Mon, 30 Jan 2012 14:15:12 +0900
> > Subject: [PATCH] Add num_to_str() for speedup /proc/stat
> > On my 8cpu box.
> > == Before patch ==
> > [root@bluextal test]# time ./stat_check.py
> > 
> > real    0m0.150s
> > user    0m0.026s
> > sys     0m0.121s
> > 
> > == After patch ==
> > [root@bluextal test]# time ./stat_check.py
> > 
> > real    0m0.055s
> > user    0m0.022s
> > sys     0m0.030s
> > 
> > Maybe it's worth to add this simple function.
> 
> I suppose so - the new infrastructure can be used elsewhere.
> 
> I tried doing the
> 
> 	if (kstst_irqs(j) == 0) {
> 		seq_putc(p, ' ');
> 		seq_putc(p, '0');
> 
> think on top of this and didn't observe any improvement.
> 
> 
> I made some changes - please review.  I'm not sure why you did "char
> tmp[66]"?
> 
Your fix seems fine to me.
I'm sorry I copied tmp[66] from number()..

and yes, 0xffffffffffffffff=18446744073709551615 , tmp[21] will be enough.

I'll prepare patch for /proc/<pid>/stat and see 'ps' and 'top' performance.

Thanks,
-Kame


  reply	other threads:[~2012-01-30 23:59 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
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 [this message]
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

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