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Date: Tue, 24 Mar 2015 16:22:19 +0000
From: Dietmar Eggemann <dietmar.eggemann@arm.com>
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To: Peter Zijlstra <peterz@infradead.org>,
        Morten Rasmussen <Morten.Rasmussen@arm.com>
CC: "mingo@redhat.com" <mingo@redhat.com>,
        "vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
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        Juri Lelli <Juri.Lelli@arm.com>,
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Subject: Re: [RFCv3 PATCH 38/48] sched: Infrastructure to query if load balancing
 is energy-aware
References: <1423074685-6336-1-git-send-email-morten.rasmussen@arm.com> <1423074685-6336-39-git-send-email-morten.rasmussen@arm.com> <20150324135613.GR23123@twins.programming.kicks-ass.net>
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On 24/03/15 13:56, Peter Zijlstra wrote:
> On Wed, Feb 04, 2015 at 06:31:15PM +0000, Morten Rasmussen wrote:
>> From: Dietmar Eggemann <dietmar.eggemann@arm.com>
>>
>> Energy-aware load balancing should only happen if the ENERGY_AWARE feature
>> is turned on and the sched domain on which the load balancing is performed
>> on contains energy data.
>> There is also a need during a load balance action to be able to query if we
>> should continue to load balance energy-aware or if we reached the tipping
>> point which forces us to fall back to the conventional load balancing
>> functionality.
>
>> @@ -7348,6 +7349,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
>>   		.cpus		= cpus,
>>   		.fbq_type	= all,
>>   		.tasks		= LIST_HEAD_INIT(env.tasks),
>> +		.use_ea		= (energy_aware() && sd->groups->sge) ? true : false,
>
> fwiw, no tipping point in that logic.

Wanted to explain why I added lv_env::use_ea. But mentioning the tipping 
point problem here seems to be a little far-fetched. Will get rid of the 
second sentence in the header.