Re: Stop machine threads are getting preemted by the rtperiod enforcement

[Peter Zijlstra]

On Wed, 2008-06-04 at 11:24 -0700, Max Krasnyansky wrote:
> 
> Peter Zijlstra wrote:
> > On Wed, 2008-06-04 at 11:07 -0700, Max Krasnyansky wrote:
> >> Peter, Ingo,
> >>
> >> Take a look at the report below (came up during isolcpu= remove discussions).
> >>
> >> It looks like stop_machine threads are getting forcefully preempted because
> >> they exceed their RT quanta. It's strange because rt period is pretty long.
> >> But given that disabling rt period logic solves the issue the machine was not
> >> really stuck.
> > 
> > Yeah, I know, I'm already looking at this
> 
> I see. Does it look like a bug in the rt period logic ?
> Or did the stop_machine thread really run for a long time (in the report that
> you got that is) ?

looks like a fun race between refreshing the period and updating
cpu_online_map.



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