Re: ksoftirqd problem
From: Frederic Weisbecker
Date: Wed Dec 30 2009 - 16:16:10 EST
On Sun, Dec 13, 2009 at 08:05:29PM +0100, Nico wrote:
>
> Hi,
>
> I recently switched to kernel 2.6.32 (self configured/compiled) and I've noticed an odd behavior on one of my servers. I run a bittorrent tracker on one of my servers and when using kernel 2.6.32, every now and then ksoftirqd will jump up to 20% of my CPU for almost a minute. The tracker has a total peers amount of ~45000 peers (if it matters) and this behavior seems to only happen under kernel 2.6.32. Switching back to kernel 2.6.31.1 on the server, ksoftirdq does not behave that way.
>
> Any thoughts?
>
> PS: please CC me as I'm not subscribed to the list
>
> Thanks :)
Hi,
I wonder if this problem still happens in 2.6.33-rc2.
A trace of softirqs during the issue would be helpful
to determine which softirq is the culprit:
mount -t debugfs /debug
echo 1 > /debug/tracing/events/irq/softirq_entry/enable
# wait a bit
echo 0 > /debug/tracing/events/irq/softirq_entry/enable
cat trace
Thanks.
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