Re: Future of NOHZ full/isolation development (was Re: [NOHZ] Remove scheduler_tick_max_deferment)

[Peter Zijlstra]

On Wed, Nov 12, 2014 at 08:26:05PM +0530, Viresh Kumar wrote:
> On 12 November 2014 19:24, Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
> > I'd rather leave that to tracepoints. Like trace_hrtimer_spurious().
> 
> Yeah, it was just to prove things right on the console without getting
> into traces.
> 
> > Or better yet: have trace_hrtimer_interrupt() which we can compare against
> > trace_hrtimer_expire_entry/exit() to check if any hrtimer callback have run
> > in the interrupt. This way we avoid workarounds like the above count.
> 
> Yeah, I also believe we better add this debug information to mainline kernel.
> I will try to get a patch for that soon.
> 
> Would it be recommended to add both trace points?
> i.e. trace_hrtimer_interrupt() and trace_hrtimer_spurious() 

I don't think you need to add anything. We already have tracepoints for
every single interrupt (and therefore also for the hrtimer one) and we
have expiry tracepoints.


--
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/