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Date: Thu, 23 Aug 2012 11:01:55 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Organization: Hitachi, Ltd., Japan
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>,
        Amit Shah <amit.shah@redhat.com>,
        Anthony Liguori <anthony@codemonkey.ws>, Arnd Bergmann <arnd@arndb.de>,
        Borislav Petkov <bp@amd64.org>, "Franch Ch. Eigler" <fche@redhat.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Herbert Xu <herbert@gondor.hengli.com.au>,
        Ingo Molnar <mingo@redhat.com>,
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        virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org,
        yrl.pp-manager.tt@hitachi.com
Subject: Re: [PATCH 2/5] trace-cmd: Use tracing directory to count CPUs
References: <20120822084251.17293.69086.stgit@ltc189.sdl.hitachi.co.jp>  <20120822084312.17293.47596.stgit@ltc189.sdl.hitachi.co.jp> <1345642893.5069.31.camel@gandalf.local.home>
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(2012/08/22 22:41), Steven Rostedt wrote:
> On Wed, 2012-08-22 at 17:43 +0900, Yoshihiro YUNOMAE wrote:
>> From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>>
>> Count debugfs/tracing/per_cpu/cpu* to determine the
>> number of CPUs.
> 
> I'm curious, do you find that sysconf doesn't return the # of CPUs the
> system has?

No, sysconf returns the number of hosts CPUs, not guests.

> I've had boxes where the per_cpu/cpu* had more cpus than the
> box actually holds. But this was a bug in the kernel, not the tool. This
> change log needs to have rational instead of just explaining what the
> patch does.

Ah, I see. Hmm, then this should be enabled by a command line
option or an environment variable.

Thank you,


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com