linux-kernel - Re: [RFC 4/4] sched/fair: Take into runnable

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Message-ID: <e997556f-8adc-2165-2e76-ce9b0229c977@arm.com>
Date:   Thu, 13 Feb 2020 18:37:19 +0000
From:   Valentin Schneider <valentin.schneider@....com>
To:     Vincent Guittot <vincent.guittot@...aro.org>, mingo@...hat.com,
        peterz@...radead.org, juri.lelli@...hat.com,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, linux-kernel@...r.kernel.org
Cc:     pauld@...hat.com, parth@...ux.ibm.com
Subject: Re: [RFC 4/4] sched/fair: Take into runnable_avg to classify group

On 2/13/20 6:32 PM, Valentin Schneider wrote:
>> @@ -7911,6 +7912,10 @@ group_has_capacity(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
>>  	if (sgs->sum_nr_running < sgs->group_weight)
>>  		return true;
>>  
>> +	if ((sgs->group_capacity * imbalance_pct) <
>> +			(sgs->group_runnable * 100))
>> +		return false;
>> +
> 
> I haven't stared long enough at patch 2, but I'll ask anyway - with this new
> condition, do we still need the next one (based on util)? AIUI
> group_runnable is >= group_util, so if group_runnable is within the allowed
> margin then group_util has to be as well.
> 

Hmph, actually util_est breaks the runnable >= util assumption I think...

>>  	if ((sgs->group_capacity * 100) >
>>  			(sgs->group_util * imbalance_pct))
>>  		return true;