Messages in this thread Patch in this message | | | Subject | Re: [PATCH] sched: Call update_group_power only for local_group | From | Suresh Siddha <> | Date | Thu, 08 Jul 2010 14:53:34 -0700 |
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On Thu, 2010-07-08 at 11:16 -0700, Peter Zijlstra wrote: > On Thu, 2010-07-08 at 10:45 -0700, Suresh Siddha wrote: > > > @@ -2433,7 +2433,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, > > > return; > > > } > > > > > > - update_group_power(sd, this_cpu); > > > + if (local_group) > > > + update_group_power(sd, this_cpu); > > > > if IDLE == CPU_NEWLY_IDLE, then all the cpu's in the local group will do > > this. Also update_group_power() can be done on only on the local cpu, > > i.e., when this_cpu == smp_processor_id() right? > > It might make sense to only update_group_power on !CPU_NEWLY_IDLE and > rely on the tick driven cpu_power updates. > > No sense in updating them in finer slices I guess. > > So how about something like: > > --- > kernel/sched_fair.c | 12 ++++++------ > 1 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c > index 9910e1b..2f05679 100644 > --- a/kernel/sched_fair.c > +++ b/kernel/sched_fair.c > @@ -2427,14 +2427,14 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, > * domains. In the newly idle case, we will allow all the cpu's > * to do the newly idle load balance. > */ > - if (idle != CPU_NEWLY_IDLE && local_group && > - balance_cpu != this_cpu) { > - *balance = 0; > - return; > + if (idle != CPU_NEWLY_IDLE && local_group) { > + if (balance_cpu != this_cpu) { > + *balance = 0; > + return; > + } > + update_group_power(sd, this_cpu); > } > > - update_group_power(sd, this_cpu); > - > /* Adjust by relative CPU power of the group */ > sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; >
I am ok with this patch (barring the currently broken aperf/mperf part).
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Also, looking at all this, don't we need to do something like this in the nohz load balance?
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 9910e1b..ae750e9 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3598,6 +3598,7 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) } raw_spin_lock_irq(&this_rq->lock); + update_rq_clock(this_rq); update_cpu_load(this_rq); raw_spin_unlock_irq(&this_rq->lock);
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