Subject: Re: ext3 allocate-with-reservation latencies
From: Lee Revell <rlrevell@joe-job.com>
To: cmm@us.ibm.com
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>
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Date: Tue, 05 Apr 2005 12:38:42 -0400
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On Mon, 2005-04-04 at 23:10 -0700, Mingming Cao wrote:
> On Tue, 2005-04-05 at 06:13 +0200, Ingo Molnar wrote:
> > * Lee Revell <rlrevell@joe-job.com> wrote:
> > 
> > > I can trigger latencies up to ~1.1 ms with a CVS checkout.  It looks
> > > like inside ext3_try_to_allocate_with_rsv, we spend a long time in this
> > > loop:
> > > 
> 
> We have not modify the reservation create algorithm for a long time.
> Sorry, I missed the background here, on which kernel did you see this
> latency? And what tests you were running?

Makes sense, I have been seeing this one for a long time.  I get it with
dbench, or when doing a CVS checkout of a large module.

Kernel is 2.6.12-rc1-RT-V0.7.43-05, with PREEMPT_DESKTOP which AFAIK
should be equivalent to mainline.

Lee

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