Messages in this thread | | | Subject | Re: [BUG nohz]: wrong user and system time accounting | From | Rik van Riel <> | Date | Tue, 28 Mar 2017 17:01:52 -0400 |
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On Tue, 2017-03-28 at 16:14 -0400, Luiz Capitulino wrote: > On Tue, 28 Mar 2017 13:24:06 -0400 > Luiz Capitulino <lcapitulino@redhat.com> wrote: > > I'm starting to suspect that the nohz code may be programming > > the tick period to be shorter than 1ms when it re-activates > > the tick. > > And I think I was right, it looks like the nohz code is programming > the tick period incorrectly when restarting the tick. The patch below > fixes things for me, but I still have some homework todo and more > testing before posting a patch for inclusion. Could you guys test it?
Your patch seems to work. I don't claim to understand why your patch makes a difference, but for this particular test case, on this particular setup, it seems to work...
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 7fe53be..9abe979 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -1152,6 +1152,7 @@ static enum hrtimer_restart > tick_sched_timer(struct hrtimer *timer) > struct pt_regs *regs = get_irq_regs(); > ktime_t now = ktime_get(); > > + ts->last_tick = now; > tick_sched_do_timer(now); > > /*
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