Messages in this thread | | | Date | Thu, 2 Oct 2008 07:33:04 -0700 | From | Arjan van de Ven <> | Subject | Re: [PATCH] Give kjournald a IOPRIO_CLASS_RT io priority |
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On Thu, 2 Oct 2008 09:46:59 -0400 Theodore Tso <tytso@mit.edu> wrote:
> On Thu, Oct 02, 2008 at 06:16:29AM -0700, Arjan van de Ven wrote: > > On Thu, 2 Oct 2008 08:04:44 -0400 > > Theodore Tso <tytso@mit.edu> wrote: > > > > > > > > > But sometimes that doesn't work (including the place where I > > > > knowingly broke it). If we can find and fix the offending > > > > piece of jbd logic (a big if) then all is peachy. > > > > > > Do we have workloads that can easily demonstrate this problem? > > > If so, we can add some tracing code which will allow us to see > > > which theory is correct, and what is actually happening. > > > > I can very easily reproduce it; my mail client (claws) stalls due to > > this several seconds at least once every 5 to 10 minutes... > > (usually when I'm typing an email.. grumble) > > Are you running with noatime or relatime?
yes; I have
mount -o remount,relatime / & for i in `pidof kjournald` ; do ionice -c1 -p $i ; done
in my /etc/rc.local
> One quick thing to try that might show what is going on is to run > debugfs on the device where your mail directory is located, while > claws is running, and then use the debugfs command "logdump -a" to > dump out the contents of the journal. You can then use ncheck and > icheck to take the FS block numbers from logdump and translate them to > inode numbers, and then from inode numbers to pathnames. That might > give us some insight as to what is going on.
I'll try (sadly I'm in a training session all day today so I might not get to it quickly)
> I can whip up a patch which adds some markers which we could use to > find out more information about what is happening.
interesting testcase of the markers concept.
-- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org
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