From: "Jörg-Volker Peetz" <jvpeetz@web.de>
To: linux-kernel@vger.kernel.org
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
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: Mon, 30 Jan 2012 09:06:13 +0100 [thread overview]
Message-ID: <4F264F75.7040601@web.de> (raw)
In-Reply-To: <1327451195.14373.28.camel@edumazet-laptop>
Eric Dumazet wrote, on 01/25/12 01:26:
> 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.
>
Wrong math, only num_possible_cpus() is divided by 32. Thus,
- unsigned size = 4096 * (1 + num_possible_cpus() / 32);
+ unsigned size = 4096 + 128 * num_possible_cpus();
<snip>
--
Best regards,
Jörg-Volker.
next prev parent reply other threads:[~2012-01-30 8:06 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
2012-01-30 8:06 ` Jörg-Volker Peetz [this message]
2012-01-30 9:25 ` Eric Dumazet
2012-01-30 10:00 ` Jörg-Volker Peetz
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