Re: Yet more softlockups.

[H. Peter Anvin]

On 07/05/2013 09:02 AM, Thomas Gleixner wrote:
> On Fri, 5 Jul 2013, Dave Jones wrote:
> > On Fri, Jul 05, 2013 at 05:15:07PM +0200, Thomas Gleixner wrote:
> >   > On Fri, 5 Jul 2013, Dave Jones wrote:
> >   >
> >   > > BUG: soft lockup - CPU#3 stuck for 23s! [trinity-child1:14565]
> >   > > perf samples too long (2519 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
> >   > > INFO: NMI handler (perf_event_nmi_handler) took too long to run: 238147.002 msecs
> >   >
> >   > So we see a softlockup of 23 seconds and the perf_event_nmi_handler
> >   > claims it did run 23.8 seconds.
> >   >
> >   > Are there more instances of NMI handler messages ?
> >
> > [ 2552.006181] perf samples too long (2511 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
> > [ 2552.008680] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 500392.002 msecs
>
> Yuck. Spending 50 seconds in NMI context surely explains a softlockup :)

Hmmm... this makes me wonder if the interrupt tracepoint stuff is at 
fault here, as it changes the IDT handling for NMI context.

	-hpa

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/