Re: [patch] rt: sysprof hrtimer fix

Frederic Weisbecker
2009-02-13T20:03:13Z

On Fri, Feb 13, 2009 at 01:49:28PM +0100, Ingo Molnar wrote:
>
> * Frederic Weisbecker <fweisbec@gmail.com> wrote:
>
> > So, just a thing.
> > -rt make the hrtimer's timers running on softirq context because the hrtimer_interrupt
> > doesn't run as a threaded interrupt, and then it is not preemptible right?
> >
> > In that case, sysprof will continue to run in hardirq context, as before, and
> > it will considerably increase the latency. And that matters here.
> > So I think it is important to put it on the reminder:
>
> hm, not sure. Do you know it numerically how much worst-case overhead it
> induces?
>
> Ingo

Not at all.
But when I find some time, I will compare some rt average tests with and without sysprof.