Re: ksoftirqd/n permanently eating 60% of a CPU

From: Louis-David Mitterrand
Date: Mon Sep 13 2010 - 03:54:13 EST


On Sun, Sep 12, 2010 at 08:57:15PM +0200, Andreas Mohr wrote:
> > Examining /proc/interrupts shows that "Local timer interrupts" are
> > mainly firing.
>
> > Strangely enough, the interrupt storm starts only 5 minutes or so after
> > bootup.
>
> And have you tried running powertop or manually (perhaps via
> sophisticated shell script) keeping a watch on
> /proc/timer[list|stats]?

Hi,

powertop seems to give a strong hint:

54.5% (250.2) [kernel core] dsp_cmx_send (dsp_cmx_send)
25.8% (118.6) usbhid-ups
5.8% ( 26.7) [ahci] <interrupt>
2.6% ( 12.0) [kernel core] usb_hcd_poll_rh_status (rh_timer_func)

Apparently dsp_cmx_send is in the mISDN stack which, in my kernel, is
compiled statically. This happens regardless of the box having isdn
hardware.
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