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Subject: Re: [PATCH] sched: Call update_group_power only for local_group
From: Suresh Siddha <suresh.b.siddha@intel.com>
Reply-To: Suresh Siddha <suresh.b.siddha@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Venkatesh Pallipadi <venki@google.com>,
       LKML <linux-kernel@vger.kernel.org>, Gautham R Shenoy <ego@in.ibm.com>,
       Joel Schopp <jschopp@austin.ibm.com>,
       Michael Neuling <mikey@neuling.org>
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Organization: Intel Corp
Date: Thu, 08 Jul 2010 10:50:16 -0700
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On Thu, 2010-07-08 at 10:49 -0700, Peter Zijlstra wrote:
> On Thu, 2010-07-08 at 10:45 -0700, Suresh Siddha wrote:
> >  
> > @@ -2456,6 +2454,9 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
> >  	init_sd_power_savings_stats(sd, sds, idle);
> >  	load_idx = get_sd_load_idx(sd, idle);
> >  
> > +	if (this_cpu == smp_processor_id())
> > +		update_group_power(sd, this_cpu);
> > +
> >  	do {
> >  		int local_group;
> 
> Which will break for nohz_idle_balance..

Then the logic is broken somewhere because update_group_power() reads
APERF/MPERF MSR's which doesn't make sense when this_cpu !=
smp_processor_id(). What am I missing?

thanks,
suresh