Re: CONFIG_NO_HZ_FULL + CONFIG_PREEMPT_RT_FULL = nogo

From: Mike Galbraith
Date: Fri Nov 08 2013 - 09:22:11 EST


On Fri, 2013-11-08 at 06:03 -0800, Paul E. McKenney wrote:
> On Fri, Nov 08, 2013 at 02:26:28PM +0100, Mike Galbraith wrote:
> > On Fri, 2013-11-08 at 04:37 -0800, Paul E. McKenney wrote:
> > > On Fri, Nov 08, 2013 at 08:31:20AM +0100, Mike Galbraith wrote:
> > > > On Thu, 2013-11-07 at 19:23 -0800, Paul E. McKenney wrote:
> > > >
> > > > > An untested patch that gets rid of the RCU_SOFTIRQs in this case is below.
> > > >
> > > > Yup, toasted.
> > >
> > > You lost me on this one. If my patch broke your system, any chance of
> > > any diagnostic information?
> >
> > No no, the RCU_SOFTIRQs are toast, history, gone.
>
> Ah, I do like that outcome much better! ;-) The scheduling-clock
> interrupts are gone (or at least reduced) as well?

No, tick shutdown needs encouragement to succeed, but there were no
RCU_SOFTIRQs on rcu_nocbs= CPUs.

> And does this mean that I can have your Tested-by?

Tested-by: Mike Galbraith <bitbucket@xxxxxxxxx>

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