From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Date: Sun, 11 Oct 2009 18:35:36 +0000 Subject: Re: lots of unplugged by timer normal or abnormal? Message-Id: <20091011183536.GS9228@kernel.dk> List-Id: References: <20091006185337.GF26949@hostway.ca> In-Reply-To: <20091006185337.GF26949@hostway.ca> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-btrace@vger.kernel.org On Sun, Oct 11 2009, Simon Kirby wrote: > On Tue, Oct 06, 2009 at 04:20:32PM -0400, Alan D. Brunelle wrote: > > > Coincidentally I was investigating something similar w/ RHEL 5.4 at this > > very moment - just wanted to know if that was a common denominator. > > > > Could you run the attached SystemTap script and send out the output? > > [You may have to get `systemtap' though...] > > Thanks for the excuse to try SystemTap. :) I have some traces, but I > don't think the UT case is abnormal. On my desktop at home, I can see > btraces such as this, which seem to show it happening often: It depends a lot on the workload. The UT will trigger if the amount of writes isn't very high - if you go above 4 queued writes, a regular unplug will trigger. So if you see if for write intensive workloads, it is almost surely a bug. For background firefox activity on your desktop, it's not unusual. If you see if for reads, it's almost always a bug. -- Jens Axboe