Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 8 Apr 2020 14:29:16 +0200 | Subject | Re: [PATCH 1/4] sched/topology: Store root domain CPU capacity sum |
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On Wed, 8 Apr 2020 at 11:50, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: > > Add the sum of (original) CPU capacity of all member CPUs to the root > domain. > > This is needed for capacity-aware SCHED_DEADLINE admission control. > > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> > --- > kernel/sched/sched.h | 11 +++++++++++ > kernel/sched/topology.c | 14 ++++++++++---- > 2 files changed, 21 insertions(+), 4 deletions(-) > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 1e72d1b3d3ce..91bd0cb0c529 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -797,6 +797,7 @@ struct root_domain { > cpumask_var_t rto_mask; > struct cpupri cpupri; > > + unsigned long sum_cpu_capacity; > unsigned long max_cpu_capacity; > > /* > @@ -2393,6 +2394,16 @@ static inline unsigned long capacity_orig_of(int cpu) > { > return cpu_rq(cpu)->cpu_capacity_orig; > } > + > +static inline unsigned long rd_capacity(int cpu) > +{ > + return cpu_rq(cpu)->rd->sum_cpu_capacity; > +} > +#else > +static inline unsigned long rd_capacity(int cpu) > +{ > + return SCHED_CAPACITY_SCALE; > +} > #endif > > /** > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 8344757bba6e..74b0c0fa4b1b 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -2052,12 +2052,17 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att > /* Attach the domains */ > rcu_read_lock(); > for_each_cpu(i, cpu_map) { > + unsigned long cap = arch_scale_cpu_capacity(i);
Why do you replace the use of rq->cpu_capacity_orig by arch_scale_cpu_capacity(i) ? There is nothing about this change in the commit message
> + > rq = cpu_rq(i); > sd = *per_cpu_ptr(d.sd, i); > > /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */ > - if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity)) > - WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig); > + if (cap > READ_ONCE(d.rd->max_cpu_capacity)) > + WRITE_ONCE(d.rd->max_cpu_capacity, cap); > + > + WRITE_ONCE(d.rd->sum_cpu_capacity, > + READ_ONCE(d.rd->sum_cpu_capacity) + cap); > > cpu_attach_domain(sd, d.rd, i); > } > @@ -2067,8 +2072,9 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att > static_branch_inc_cpuslocked(&sched_asym_cpucapacity); > > if (rq && sched_debug_enabled) { > - pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", > - cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); > + pr_info("root domain span: %*pbl (capacity = %lu max cpu_capacity = %lu)\n", > + cpumask_pr_args(cpu_map), rq->rd->sum_cpu_capacity, > + rq->rd->max_cpu_capacity); > } > > ret = 0; > -- > 2.17.1 >
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