Subject: Re: 2.6.23-rc6: hanging ext3 dbench tests
From: Badari Pulavarty <pbadari@gmail.com>
To: Andy Whitcroft <apw@shadowen.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, sct@redhat.com,
       Andrew Morton <akpm@linux-foundation.org>, adilger@clusterfs.com,
       ext4 <linux-ext4@vger.kernel.org>, lkml <linux-kernel@vger.kernel.org>,
       mel@csn.ul.ie
In-Reply-To: <20070919181546.GA4343@shadowen.org>
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Date: Mon, 24 Sep 2007 11:01:58 -0700
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Hi Andy,

I managed to reproduce the dbench problem. (not sure if its the same
thing or not - but symptoms are same). My problem has nothing to do 
with ext3. I can produce it on ext2, jfs also.

Whats happening on my machine is ..

dbench forks of 4 children and sends them a signal to start the work.
3 out of 4 children gets the signal and does the work. One of the child
never gets the signal so, it waits forever in pause(). So, parent waits
for a longtime to kill it.

BTW, I was trying to find out when this problem started showing up.
So far, I managed to track it to 2.6.23-rc4. (2.6.23-rc3 doesn't seem
to have this problem). I am going to do bi-sect and find out which
patch caused this.

I am using dbench-2.0 which consistently reproduces the problem on
my x86-64 box. Did you find anything new with your setup ?

Thanks,
Badari


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