Messages in this thread | | | Date | Fri, 7 Oct 2022 16:36:58 -0700 | From | Ricardo Neri <> | Subject | Re: [RFC PATCH 10/23] sched/fair: Use classes of tasks when selecting a busiest runqueue |
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On Tue, Sep 27, 2022 at 01:25:57PM +0200, Peter Zijlstra wrote: > On Fri, Sep 09, 2022 at 04:11:52PM -0700, Ricardo Neri wrote: > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 7368a0b453ee..085b1f75d90b 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -10009,6 +10009,7 @@ static struct rq *find_busiest_queue(struct lb_env *env, > > int i; > > > > for_each_cpu_and(i, sched_group_span(group), env->cpus) { > > + int busiest_class_delta_score = INT_MIN; > > You sure you want to break ties toward a negative IPC 'improvement' ?
Yes. We may have a negative IPC class delta if the destination CPU has lower prioriy than the CPUs in the busiest group. This may occur when the busiest group is a core with more than one busy SMT sibling.
> > > unsigned long capacity, load, util; > > unsigned int nr_running; > > enum fbq_type rt; > > @@ -10118,6 +10119,20 @@ static struct rq *find_busiest_queue(struct lb_env *env, > > if (busiest_nr < nr_running) { > > busiest_nr = nr_running; > > busiest = rq; > > + } else if (sched_task_classes_enabled() && > > + busiest_nr == nr_running) { > > + int curr_class_delta_score; > > + > > + curr_class_delta_score = arch_get_task_class_score(rq->curr->class, > > + env->dst_cpu) - > > + arch_get_task_class_score(rq->curr->class, > > + cpu_of(rq)); > > *sigh*, you really couldn't find a more ugly layout if you tried. > > Perhaps use less than novella length identifiers?
Sure, I will revisit the naming of the identifiers.
Thanks and BR, Ricardo
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