Messages in this thread | | | Date | Wed, 03 Jul 2013 17:11:45 +0800 | From | Michael Wang <> | Subject | Re: [PATCH v2] sched: smart wake-affine |
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On 07/03/2013 04:50 PM, Peter Zijlstra wrote: > On Wed, Jul 03, 2013 at 02:10:32PM +0800, Michael Wang wrote: >> +static int wake_wide(struct task_struct *p) >> +{ >> + int factor = nr_cpus_node(cpu_to_node(smp_processor_id())); > > That's still a cpumask_weight() in there...
Exactly, although the scale is lower but still it's a mask...
> we should avoid that. How about something like the below:
Amazing, cost will be lowest when we got such counter, will make them a patch set and test again ;-)
Regards, Michael Wang
> >> + >> + /* >> + * Yeah, it's the switching-frequency, could means many wakee or >> + * rapidly switch, use factor here will just help to automatically >> + * adjust the loose-degree, so bigger node will lead to more pull. >> + */ >> + if (p->nr_wakee_switch > factor) { >> + /* >> + * wakee is somewhat hot, it needs certain amount of cpu >> + * resource, so if waker is far more hot, prefer to leave >> + * it alone. >> + */ >> + if (current->nr_wakee_switch > (factor * p->nr_wakee_switch)) >> + return 1; >> + } >> + >> + return 0; >> +} > > --- > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 9b1f2e5..166ab9b 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -5081,18 +5083,23 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu) > * two cpus are in the same cache domain, see cpus_share_cache(). > */ > DEFINE_PER_CPU(struct sched_domain *, sd_llc); > +DEFINE_PER_CPU(int, sd_llc_size); > DEFINE_PER_CPU(int, sd_llc_id); > > static void update_top_cache_domain(int cpu) > { > struct sched_domain *sd; > int id = cpu; > + int size = 1; > > sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); > - if (sd) > + if (sd) { > id = cpumask_first(sched_domain_span(sd)); > + size = cpumask_weight(sched_domain_span(sd)); > + } > > rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); > + per_cpu(sd_llc_size, cpu) = size; > per_cpu(sd_llc_id, cpu) = id; > } > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index ef0a7b2..c992f58 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -595,6 +595,7 @@ static inline struct sched_domain *highest_flag_domain(int cpu, int flag) > } > > DECLARE_PER_CPU(struct sched_domain *, sd_llc); > +DECLARE_PER_CPU(int, sd_llc_size); > DECLARE_PER_CPU(int, sd_llc_id); > > struct sched_group_power { > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3175,7 +3175,7 @@ static inline unsigned long effective_lo > > static int wake_wide(struct task_struct *p) > { > - int factor = nr_cpus_node(cpu_to_node(smp_processor_id())); > + int factor = this_cpu_read(sd_llc_size); > > /* > * Yeah, it's the switching-frequency, could means many wakee or > > -- > 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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