lkml.org 
[lkml]   [2010]   [Nov]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift
On Thu, Nov 18, 2010 at 01:51:44PM -0600, Jason Wessel wrote:
> > So the problem is when the nmi watchdog is enabled, the perf event is
> > 'active' and thus tries to read the counter value. Because it is always
> > zero, perf just assumes the counter overflowed and the NMI is his.
> >
> > Not sure how to fix it yet, other than include the logic that detects we
> > are on a guest and disable perf??
> >
> >
>
> I highly doubt we want to disable perf. I would rather use the source
> and fix the nmi emulation in KVM/Qemu after we hear back the results

Well I think Peter does not have a positive opinion about emulating perf
inside a guest. Nor are the KVM folks having much success in doing so.

Just to clarify, perf counter emulation is _not_ implemented in kvm.
Therefore disabling perf in the guest makes sense until someone gets
around to actually writing the emulation code for perf in a guest. :-)

Cheers,
Don


\
 
 \ /
  Last update: 2010-11-18 21:11    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site