Re: x86-tip tsc/tick gripage

From: Ingo Molnar
Date: Wed Apr 26 2017 - 04:23:29 EST



* Mike Galbraith <efault@xxxxxx> wrote:

> On Wed, 2017-04-26 at 10:02 +0200, Mike Galbraith wrote:
>
> > tip v4.11-rc8-893-g8ec9e12aff06, trusty ole 8 socket (X7560) DL980 G7
>
> Ew, DL980 then turned into unhappy RCU camper.
>
> [ 316.980923] basemono: 316956000000 ts->next_tick: 316380000000 dev->next_event: 316956005002
> [ 689.893122] INFO: rcu_sched detected stalls on CPUs/tasks:

Probably RCU unrelated.

I have temporarily removed the current timers/urgent lineup from -tip:

098991fccfc7: nohz: Print more debug info in tick_nohz_stop_sched_tick()
22aa2ad45fd8: tick: Make sure tick timer is active when bypassing reprogramming
d58bd60c773d: nohz: Fix again collision between tick and other hrtimers

... and have reintegrated tip:master, so it should be back to working I think.

Does this solve the warning and the RCU stalls on your boxes?

Thanks,

Ingo