From: matthias.bgg@googlemail.com (Matthias Brugger)
To: kernelnewbies@lists.kernelnewbies.org
Subject: blktrace vs ftrace
Date: Wed, 08 Feb 2012 11:59:26 +0100 [thread overview]
Message-ID: <4F32558E.3090804@gmail.com> (raw)
In-Reply-To: <CAGdaadZ44SMbsmx=iuBLmf1+gHPD7tTKpEMhyAYOXuAQn_OOyA@mail.gmail.com>
Hi,
On 02/03/2012 06:59 AM, Mulyadi Santosa wrote:
>
> I could only offer this explanation:
> blktrace traces events in block level. In this level, I/O is likely
> serialized....unless you have more than one physical disks.
>
> in ftrace, you see events right before it hits block level operation.
> Somewhere between VFS, filesystem operation and I/O scheduling which
> deals with queue reordering. In this case, parallel operation is
> likely to happen because more than processes could submit read or
> write.
If I understand the patch which introduces the blk tracer to ftrace
(http://lwn.net/Articles/315508/) just uses the blktrace interface. So I
wonder why using this influences the I/O behaviour.
Best regards,
Matthias
next prev parent reply other threads:[~2012-02-08 10:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-02 10:20 blktrace vs ftrace Matthias Brugger
2012-02-02 18:15 ` Mulyadi Santosa
2012-02-02 19:06 ` Matthias Brugger
2012-02-03 5:59 ` Mulyadi Santosa
2012-02-08 10:59 ` Matthias Brugger [this message]
2012-02-08 17:04 ` Mulyadi Santosa
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