From: Eric Dumazet <eric.dumazet@gmail.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
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: Wed, 25 Jan 2012 01:26:35 +0100 [thread overview]
Message-ID: <1327451195.14373.28.camel@edumazet-laptop> (raw)
In-Reply-To: <20120125091818.45e00b3c.kamezawa.hiroyu@jp.fujitsu.com>
Le mercredi 25 janvier 2012 à 09:18 +0900, KAMEZAWA Hiroyuki a écrit :
> BTW, what is the reason of this change ?
>
> > - unsigned size = 4096 * (1 + num_possible_cpus() / 32);
> > + unsigned size = 1024 + 128 * num_possible_cpus();
>
> I think size of buffer is affected by the number of online cpus.
> (Maybe 128 is enough but please add comment why 128 ?)
>
There is no change, as 4096/32 is 128 bytes per cpu.
Only change is granularity is not any more 32 cpus, but one.
Of course, kmalloc() is going to roundup to next power of two anyway.
So real allocation is bigger, unless we switch to vmalloc() eventually.
next prev parent reply other threads:[~2012-01-25 0:26 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
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 [this message]
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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