Re: [PATCH RESEND] nohz: Affining unpinned timers

[Frederic Weisbecker <fweisbec@gmail.com>]

On Mon, Jul 06, 2015 at 07:18:22PM +0200, Thomas Gleixner wrote:
> On Mon, 6 Jul 2015, Frederic Weisbecker wrote:
> > I hope everybody received the patch because there is a ";" after each address :-)
> > 
> > On Tue, Jun 23, 2015 at 02:01:33PM +0530, Vatika Harlalka wrote:
> > > The problem addressed in this patch is about affining unpinned timers.
> > > Adaptive or Full Dynticks CPUs should not be disturbed by unnecessary
> > > jitter due to firing of such timers on them.
> > > This patch will affine timers to online CPUs which are not Full Dynticks
> > > in FULL_NOHZ configured systems. It will not bring about functional
> > > changes if NOHZ_FULL is not configured, because is_housekeeping_cpu()
> > > always returns true in CONFIG_NO_HZ_FULL=n.
> > > 
> > > Signed-off by: Vatika Harlalka <vatikaharlalka@gmail.com>
> > 
> > The patch looks good to me. Peter, Thomas, are you ok with it too?
> 
> By some definition of OK. The overhead of this is growing and growing.
> 
> We really need to make this a pull not a push model.

I'm currently working toward that.
See "[PATCH 0/8] tick/nohz: Tick dependency quick check + cleanups" as a
first step.

Now for this very patch, I don't know how we could make it better. Any
suggestion?

> Thanks,
> 
> 	tglx