# Re: clocksource\_watchdog causing scheduling of timers every second (was \[v13\] support "task\_isolation" mode)

- From: Paul E. McKenney \<hidden\>
- Date: 2016-08-12 16:19:31 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2016/08/4813148
- Thread: https://ratatoskr.run/linux-api/2016/07/4795325/t.md

```text
On Fri, Aug 12, 2016 at 04:26:13PM +0200, Frederic Weisbecker wrote:
> On Fri, Aug 12, 2016 at 09:23:13AM -0500, Christoph Lameter wrote:
> > On Thu, 11 Aug 2016, Paul E. McKenney wrote:
> > 
> > > Heh!  The only really good idea is for clocks to be reliably in sync.
> > >
> > > But if they go out of sync, what do you want to do instead?
> > 
> > For a NOHZ task? Write a message to the syslog and reenable tick.

Fair enough!  Kicking off a low-priority task would achieve the latter
but not necessarily the former.  And of course assumes that the worker
thread is at real-time priority with various scheduler anti-starvation
features disabled.

> Indeed, a strong clocksource is a requirement for a full tickless machine.

No disagrement here!  ;-)

							Thanx, Paul

```