Messages in this thread | | | Date | Wed, 9 Sep 2015 15:00:58 +0900 | From | Byungchul Park <> | Subject | Re: [RFC] sched: make update_cpu_load_active care more than one tick |
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On Tue, Aug 18, 2015 at 08:39:27AM +0900, Byungchul Park wrote: > On Thu, Aug 13, 2015 at 06:35:24PM +0900, byungchul.park@lge.com wrote: > > From: Byungchul Park <byungchul.park@lge.com> > > > > i found do_timer accounts other than one tick, so i made > > update_cpu_load_active care that. > > > > is it intended because of its overhead? > > hello, > > is there anyone who can tell me any opinion about this concern? > > > > > Signed-off-by: Byungchul Park <byungchul.park@lge.com> > > --- > > kernel/sched/fair.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index ffa70dc..cd3d98f 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -4506,12 +4506,15 @@ void update_cpu_load_nohz(void) > > */ > > void update_cpu_load_active(struct rq *this_rq) > > { > > + unsigned long curr_jiffies = READ_ONCE(jiffies); > > + unsigned long pending_updates; > > unsigned long load = this_rq->cfs.runnable_load_avg; > > /* > > * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). > > */ > > - this_rq->last_load_update_tick = jiffies; > > - __update_cpu_load(this_rq, load, 1); > > + pending_updates = curr_jiffies - this_rq->last_load_update_tick;
is it expensive to deal with this correction here?
in my QEMU machine, pending_updates appears to be more than 10, however current code assumes it to be 1 unconditionally.
if this correction is valid, i will resend this with adding commit msg.
> > + this_rq->last_load_update_tick = curr_jiffies; > > + __update_cpu_load(this_rq, load, pending_updates); > > } > > > > /* Used instead of source_load when we know the type == 0 */ > > -- > > 1.7.9.5 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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