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Date: Wed, 25 Jul 2012 18:13:08 +0900
From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        linux-kernel@vger.kernel.org,
        Herbert Xu <herbert@gondor.hengli.com.au>,
        Arnd Bergmann <arnd@arndb.de>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        yrl.pp-manager.tt@hitachi.com, qemu-devel@nongnu.org,
        Borislav Petkov <bp@amd64.org>,
        virtualization@lists.linux-foundation.org,
        "Franch Ch. Eigler" <fche@redhat.com>, Ingo Molnar <mingo@redhat.com>,
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        Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
        Dhaval Giani <dhaval.giani@gmail.com>
Subject: Re: Re: Re: [RFC PATCH 0/6] virtio-trace: Support virtio-trace
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Hi Stefan,

(2012/07/24 22:41), Stefan Hajnoczi wrote:
> On Tue, Jul 24, 2012 at 12:19 PM, Yoshihiro YUNOMAE
> <yoshihiro.yunomae.ez@hitachi.com> wrote:
>>>> Are you using text formatted ftrace?
>> No, currently using raw format, but　we'd like to reformat it in text.
>
> Capturing the info necessary to translate numbers into symbols is one
> of the problems of host<->guest tracing so I'm curious how you handle
> this :).

Right, your consideration is true.

> Apologies for my lack of ftrace knowledge but how useful is the raw
> tracing data on the host?  How do you pretty-print it in
> human-readable form?

perf and trace-cmd can actually translate raw-formatted trace data to
text-formatted trace data by using information of kernel or trace
format under tracing/events directory in debugfs. In the same way, if
the information of a guest is exported to a host, we can translate
raw trace data of a guest to text trace data on a host. We will use
9pfs to export that.

Thank you,

-- 
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@hitachi.com