Messages in this thread | | | Date | Tue, 14 Jul 2015 11:26:45 +0900 | From | Byungchul Park <> | Subject | Re: [PATCH v2] sched: let __sched_period() use rq's nr_running |
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On Mon, Jul 13, 2015 at 06:25:35PM +0900, Byungchul Park wrote: > On Mon, Jul 13, 2015 at 10:26:09AM +0200, Peter Zijlstra wrote: > > On Fri, Jul 10, 2015 at 05:11:30PM +0900, byungchul.park@lge.com wrote: > > > From: Byungchul Park <byungchul.park@lge.com> > > > > > > __sched_period() returns a period which a rq can have. the period has to be > > > stretched by the number of task *the rq has*, when nr_running > nr_latency. > > > otherwise, task slice can be very smaller than sysctl_sched_min_granularity > > > depending on the position of tg hierarchy when CONFIG_FAIR_GROUP_SCHED. > > > > > > Signed-off-by: Byungchul Park <byungchul.park@lge.com> > > > --- > > > kernel/sched/fair.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > > index 09456fc..8ae7aeb 100644 > > > --- a/kernel/sched/fair.c > > > +++ b/kernel/sched/fair.c > > > @@ -635,7 +635,7 @@ static u64 __sched_period(unsigned long nr_running) > > > */ > > > static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) > > > { > > > - u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); > > > + u64 slice = __sched_period(rq_of(cfs_rq)->nr_running + !se->on_rq); > > > > > > for_each_sched_entity(se) { > > > struct load_weight *load; > > > > This really doesn't make sense; look at what that > > for_each_sched_entity() loop does below this. > > hello, > > for_each_sched_entity() loop is distributing slice to se with consideration > for both hierarchy and its weight, walking from the passed se to the top rq. > > i am just talking about how to get a whole period value. my question is > "why does it use local cfs's nr_running to get a whole period value?".
i need to modify my patch more, i admit.
but i have a question, do you think it is right to use local cfs's nr_running to get a whole period value?
> > > > > I agree that sched_slice() is a difficult proposition in the face of > > cgroup, but everything is, cgroups suck arse, they make everything hard. > > i don't make an issue of the way for cgroups to work though it already have > many problems as you said. > > thank you for commenting, > byungchul > > > -- > > 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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