Messages in this thread | | | Date | Wed, 20 Nov 2019 22:04:40 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/6] sched/cputime: Support other fields on kcpustat_field() |
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On Wed, Nov 20, 2019 at 12:51:42PM +0100, Ingo Molnar wrote: > * Frederic Weisbecker <frederic@kernel.org> wrote:
> > + /* > > + * Nice VS unnice cputime accounting may be inaccurate if > > + * the nice value has changed since the last vtime update. > > + * But proper fix would involve interrupting target on nice > > + * updates which is a no go on nohz_full. > > Well, we actually already interrupt the target in both sys_nice() and > sys_setpriority() etc. syscall variants: we call set_user_nice() which > calls resched_curr() and the task is sent an IPI and runs through a > reschedule.
I think we can easily avoid doing that IPI when we find it is the only task on that runqueue. Which is exactly the case for NOHZ_FULL.
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