From: Arjan van de Ven <arjan@infradead.org>
To: "J.A. Magallón" <jamagallon@ono.com>
Cc: Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: Re: Finding what is stuck...
Date: Wed, 3 Sep 2008 16:50:14 -0700 [thread overview]
Message-ID: <20080903165014.134cb5b9@infradead.org> (raw)
In-Reply-To: <20080904010043.408b3f03@one.home>
On Thu, 4 Sep 2008 01:00:43 +0200
"J.A. Magallón" <jamagallon@ono.com> wrote:
> On Mon, 1 Sep 2008 17:08:12 -0700, Arjan van de Ven
> <arjan@infradead.org> wrote:
>
> > On Tue, 2 Sep 2008 02:04:47 +0200
> > "J.A. Magallón" <jamagallon@ono.com> wrote:
> >
> > > Hi all...
> > >
> > > I'm running 2.6.27-rc5-git2 on an Aspire One.
> > > The system is in general pretty responsive, but sometimes it just
> > > gets totally stuck. Even the mouse stops.
> > >
> > > It looks related to disk (SSD) access, but I'm not totally sure.
> > > Is there any way to find what is getting stuck ? I know that SSDs
> > > can be slow on write, I don't mind if the system is faster or
> > > slower (it's small :))), but if the speed is constant. That
> > > occasional pauses are strange, like if SSD flushing gets stuck on
> > > BKL (I know, no idea about what I talk...).
> > >
> > > I'm using ext3 fs, noop iosched. But as I say, I'm not sure that
> > > the disk writes are the culprit.
> > >
> > > Any idea about how to find this ?
> >
> > Have you tried to run "latencytop"?
> > (you need to enable this in the kernel config as well)
> >
> > it tends to (for me at least) point out very well where stalls
> > happen, or at least, what the system is doing when they happen.
> >
> > (hint: make sure you do "make install" before running it)
> >
>
> These are some shots of latencytop while working. I copied the screen
> when I saw any very high timing...
>
wow bad ones..
one thing to note.. you have *something* doing fsync() a lot it seems
(latencytop is likely to tell you which one it is); fsync on ext3 is
really expensive, especially on an ssd that is slow to write to.
--
If you want to reach me at my work email, use arjan@linux.intel.com
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
next prev parent reply other threads:[~2008-09-03 23:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-02 0:04 Finding what is stuck J.A. Magallón
2008-09-02 0:08 ` Arjan van de Ven
2008-09-02 0:12 ` J.A. Magallón
2008-09-03 23:00 ` J.A. Magallón
2008-09-03 23:50 ` Arjan van de Ven [this message]
2008-09-02 1:53 ` Jan Knutar
-- strict thread matches above, loose matches on Subject: below --
2008-09-02 9:34 Alan Jenkins
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20080903165014.134cb5b9@infradead.org \
--to=arjan@infradead.org \
--cc=jamagallon@ono.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.