From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Arnd Bergmann <arnd@arndb.de>,
qemu-devel@nongnu.org, Frederic Weisbecker <fweisbec@gmail.com>,
linux-kernel@vger.kernel.org, Borislav Petkov <bp@amd64.org>,
virtualization@lists.linux-foundation.org,
"Franch Ch. Eigler" <fche@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Anthony Liguori <anthony@codemonkey.ws>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Amit Shah <amit.shah@redhat.com>,
yrl.pp-manager.tt@hitachi.com
Subject: Re: [PATCH 2/5] trace-cmd: Use tracing directory to count CPUs
Date: Thu, 23 Aug 2012 12:00:57 +0900 [thread overview]
Message-ID: <50359CE9.3000509@hitachi.com> (raw)
In-Reply-To: <50358F13.1030607@hitachi.com>
(2012/08/23 11:01), Masami Hiramatsu wrote:
> (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.
Oops, I misunderstood. I'll add more comment for why this
should be tried instead of sysconf.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
WARNING: multiple messages have this Message-ID (diff)
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
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>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org,
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
Date: Thu, 23 Aug 2012 12:00:57 +0900 [thread overview]
Message-ID: <50359CE9.3000509@hitachi.com> (raw)
In-Reply-To: <50358F13.1030607@hitachi.com>
(2012/08/23 11:01), Masami Hiramatsu wrote:
> (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.
Oops, I misunderstood. I'll add more comment for why this
should be tried instead of sysconf.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
WARNING: multiple messages have this Message-ID (diff)
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Arnd Bergmann <arnd@arndb.de>,
qemu-devel@nongnu.org, Frederic Weisbecker <fweisbec@gmail.com>,
Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org, Borislav Petkov <bp@amd64.org>,
virtualization@lists.linux-foundation.org,
"Franch Ch. Eigler" <fche@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Anthony Liguori <anthony@codemonkey.ws>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Amit Shah <amit.shah@redhat.com>,
yrl.pp-manager.tt@hitachi.com
Subject: Re: [Qemu-devel] [PATCH 2/5] trace-cmd: Use tracing directory to count CPUs
Date: Thu, 23 Aug 2012 12:00:57 +0900 [thread overview]
Message-ID: <50359CE9.3000509@hitachi.com> (raw)
In-Reply-To: <50358F13.1030607@hitachi.com>
(2012/08/23 11:01), Masami Hiramatsu wrote:
> (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.
Oops, I misunderstood. I'll add more comment for why this
should be tried instead of sysconf.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
next prev parent reply other threads:[~2012-08-23 3:00 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 8:42 [PATCH 0/5] trace-cmd: Add a recorder readable feature for virtio-trace Yoshihiro YUNOMAE
2012-08-22 8:42 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-22 8:42 ` Yoshihiro YUNOMAE
2012-08-22 8:43 ` [PATCH 1/5] trace-cmd: Use TRACE_DIR envrionment variable if defined Yoshihiro YUNOMAE
2012-08-22 8:43 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-22 8:43 ` Yoshihiro YUNOMAE
2012-08-22 13:37 ` Steven Rostedt
2012-08-22 13:37 ` [Qemu-devel] " Steven Rostedt
2012-08-22 13:37 ` Steven Rostedt
2012-08-22 8:43 ` [PATCH 2/5] trace-cmd: Use tracing directory to count CPUs Yoshihiro YUNOMAE
2012-08-22 8:43 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-22 8:43 ` Yoshihiro YUNOMAE
2012-08-22 13:41 ` Steven Rostedt
2012-08-22 13:41 ` [Qemu-devel] " Steven Rostedt
2012-08-22 13:41 ` Steven Rostedt
2012-08-23 2:01 ` Masami Hiramatsu
2012-08-23 2:01 ` [Qemu-devel] " Masami Hiramatsu
2012-08-23 2:01 ` Masami Hiramatsu
2012-08-23 3:00 ` Masami Hiramatsu [this message]
2012-08-23 3:00 ` [Qemu-devel] " Masami Hiramatsu
2012-08-23 3:00 ` Masami Hiramatsu
2012-08-23 9:08 ` Steven Rostedt
2012-08-23 9:08 ` [Qemu-devel] " Steven Rostedt
2012-08-23 9:08 ` Steven Rostedt
2012-08-23 12:30 ` Masami Hiramatsu
2012-08-23 12:30 ` [Qemu-devel] " Masami Hiramatsu
2012-08-23 12:30 ` Masami Hiramatsu
2012-08-22 8:43 ` [PATCH 3/5] trace-cmd: Support trace-agent of virtio-trace Yoshihiro YUNOMAE
2012-08-22 8:43 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-22 8:43 ` Yoshihiro YUNOMAE
2012-08-22 13:51 ` Steven Rostedt
2012-08-22 13:51 ` [Qemu-devel] " Steven Rostedt
2012-08-22 13:51 ` Steven Rostedt
2012-08-23 3:13 ` Yoshihiro YUNOMAE
2012-08-23 3:13 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-23 3:13 ` Yoshihiro YUNOMAE
2012-08-22 8:43 ` [PATCH 4/5] trace-cmd: Add non-blocking option for open() and splice_read() Yoshihiro YUNOMAE
2012-08-22 8:43 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-22 8:43 ` Yoshihiro YUNOMAE
2012-08-22 8:43 ` [PATCH 5/5] trace-cmd: Use polling function Yoshihiro YUNOMAE
2012-08-22 8:43 ` [Qemu-devel] " Yoshihiro YUNOMAE
2012-08-22 8:43 ` Yoshihiro YUNOMAE
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