Re: [RFC 4/7] change kernel accounting to include steal time

[Marcelo Tosatti <mtosatti@redhat.com>]

On Thu, Aug 26, 2010 at 09:33:02PM -0300, Glauber Costa wrote:
> On Thu, Aug 26, 2010 at 08:12:40PM -0300, Marcelo Tosatti wrote:
> > On Thu, Aug 26, 2010 at 06:40:36PM -0300, Glauber Costa wrote:
> > > On Thu, Aug 26, 2010 at 04:14:47PM -0500, Anthony Liguori wrote:
> > > > On 08/26/2010 03:28 PM, Glauber Costa wrote:
> > > > >
> > > > >>+   if (delta>  1000UL)
> > > > >>+               touch_softlockup_watchdog();
> > > > >>+
> > > > >>
> > > > >>This will break authentic soft lockup detection whenever qemu processing
> > > > >>takes more than 1s.
> > > > >This should be 10s. 1000UL is a typo.
> > > > 
> > > > I was wondering that when I first saw the patch..  10s is the
> > > > default detection time but it's actually run time configurable so
> > > > hard coding 10s is not correct.
> > 
> > This is not what i'm referring to. The code above will disable
> > softlockup detection in case of a vcpu blocked in qemu for longer than
> > softlockup threshold, which is a legitimate case.
> This is equivalent to a hardware so broken it can't even send
> an NMI. Not sure we should worry too much about it.

Well, take the virtio-net issues for example. You'd disable reporting
for those.