sched: Micro-optimize the smart wake-affine logic
Smart wake-affine is using node-size as the factor currently, but the overhead of the mask operation is high. Thus, this patch introduce the 'sd_llc_size' percpu variable, which will record the highest cache-share domain size, and make it to be the new factor, in order to reduce the overhead and make it more reasonable. Tested-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Tested-by: Michael Wang <wangyun@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Michael Wang <wangyun@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Link: http://lkml.kernel.org/r/51D5008E.6030102@linux.vnet.ibm.com [ Tidied up the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -5083,18 +5083,23 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu)
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* two cpus are in the same cache domain, see cpus_share_cache().
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* two cpus are in the same cache domain, see cpus_share_cache().
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*/
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*/
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DEFINE_PER_CPU(struct sched_domain *, sd_llc);
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DEFINE_PER_CPU(struct sched_domain *, sd_llc);
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DEFINE_PER_CPU(int, sd_llc_size);
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DEFINE_PER_CPU(int, sd_llc_id);
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DEFINE_PER_CPU(int, sd_llc_id);
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static void update_top_cache_domain(int cpu)
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static void update_top_cache_domain(int cpu)
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{
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{
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struct sched_domain *sd;
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struct sched_domain *sd;
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int id = cpu;
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int id = cpu;
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int size = 1;
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sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
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sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
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if (sd)
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if (sd) {
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id = cpumask_first(sched_domain_span(sd));
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id = cpumask_first(sched_domain_span(sd));
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size = cpumask_weight(sched_domain_span(sd));
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}
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rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
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rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
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per_cpu(sd_llc_size, cpu) = size;
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per_cpu(sd_llc_id, cpu) = id;
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per_cpu(sd_llc_id, cpu) = id;
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}
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}
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@ -3175,7 +3175,7 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu,
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static int wake_wide(struct task_struct *p)
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static int wake_wide(struct task_struct *p)
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{
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{
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int factor = nr_cpus_node(cpu_to_node(smp_processor_id()));
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int factor = this_cpu_read(sd_llc_size);
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/*
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/*
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* Yeah, it's the switching-frequency, could means many wakee or
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* Yeah, it's the switching-frequency, could means many wakee or
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@ -594,6 +594,7 @@ static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
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}
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}
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DECLARE_PER_CPU(struct sched_domain *, sd_llc);
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DECLARE_PER_CPU(struct sched_domain *, sd_llc);
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DECLARE_PER_CPU(int, sd_llc_size);
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DECLARE_PER_CPU(int, sd_llc_id);
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DECLARE_PER_CPU(int, sd_llc_id);
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struct sched_group_power {
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struct sched_group_power {
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