Messages in this thread Patch in this message | | | Date | Fri, 14 May 2021 11:47:45 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 5/6] sched/fair: Consider SMT in ASYM_PACKING load balance |
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On Thu, May 13, 2021 at 08:49:08AM -0700, Ricardo Neri wrote: > include/linux/sched/topology.h | 1 + > kernel/sched/fair.c | 101 +++++++++++++++++++++++++++++++++ > 2 files changed, 102 insertions(+) > > diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h > index 8f0f778b7c91..43bdb8b1e1df 100644 > --- a/include/linux/sched/topology.h > +++ b/include/linux/sched/topology.h > @@ -57,6 +57,7 @@ static inline int cpu_numa_flags(void) > #endif > > extern int arch_asym_cpu_priority(int cpu); > +extern bool arch_asym_check_smt_siblings(void); > > struct sched_domain_attr { > int relax_domain_level; > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index c8b66a5d593e..3d6cc027e6e6 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -106,6 +106,15 @@ int __weak arch_asym_cpu_priority(int cpu) > return -cpu; > } > > +/* > + * For asym packing, first check the state of SMT siblings before deciding to > + * pull tasks. > + */ > +bool __weak arch_asym_check_smt_siblings(void) > +{ > + return false; > +} > + > /* > * The margin used when comparing utilization with CPU capacity. > *
> @@ -8458,6 +8550,9 @@ sched_asym(struct lb_env *env, struct sd_lb_stats *sds, struct sg_lb_stats *sgs > if (group == sds->local) > return false; > > + if (arch_asym_check_smt_siblings()) > + return asym_can_pull_tasks(env->dst_cpu, sds, sgs, group); > + > return sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu); > }
So I'm thinking that this is a property of having ASYM_PACKING at a core level, rather than some arch special. Wouldn't something like this be more appropriate?
--- --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -57,7 +57,6 @@ static inline int cpu_numa_flags(void) #endif extern int arch_asym_cpu_priority(int cpu); -extern bool arch_asym_check_smt_siblings(void); struct sched_domain_attr { int relax_domain_level; --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -107,15 +107,6 @@ int __weak arch_asym_cpu_priority(int cp } /* - * For asym packing, first check the state of SMT siblings before deciding to - * pull tasks. - */ -bool __weak arch_asym_check_smt_siblings(void) -{ - return false; -} - -/* * The margin used when comparing utilization with CPU capacity. * * (default: ~20%) @@ -8550,7 +8541,8 @@ sched_asym(struct lb_env *env, struct sd if (group == sds->local) return false; - if (arch_asym_check_smt_siblings()) + if ((sds->local->flags & SD_SHARE_CPUCAPACITY) || + (group->flags & SD_SHARE_CPUCAPACITY)) return asym_can_pull_tasks(env->dst_cpu, sds, sgs, group); return sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu);
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