On Tue, 2017-03-28 at 16:14 -0400, Luiz Capitulino wrote: > 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?
I spoke too soon. After half an hour of runtime, things have gotten aligned to give me about 50/50 user time and system time with your test case, again. This is on an 8 VCPU virtual machine, with nohz_full=2-7, and the test case running on one of the nohz_full CPUs. > 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); > > /*
