linux-kernel - Re: [Patch v4 3/6] sched/fair: Enable CFS periodic tick to update thermal pressure

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Date:   Wed, 30 Oct 2019 17:41:21 -0400
From:   Thara Gopinath <thara.gopinath@...aro.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     mingo@...hat.com, ionela.voinescu@....com,
        vincent.guittot@...aro.org, rui.zhang@...el.com,
        edubezval@...il.com, qperret@...gle.com,
        linux-kernel@...r.kernel.org, amit.kachhap@...il.com,
        javi.merino@...nel.org, daniel.lezcano@...aro.org
Subject: Re: [Patch v4 3/6] sched/fair: Enable CFS periodic tick to update
 thermal pressure

On 10/28/2019 11:24 AM, Peter Zijlstra wrote:
> On Tue, Oct 22, 2019 at 04:34:22PM -0400, Thara Gopinath wrote:
>> Introduce support in CFS periodic tick to trigger the process of
>> computing average thermal pressure for a cpu.
>>
>> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
>> ---
>>  kernel/sched/fair.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 682a754..4f9c2cb 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -21,6 +21,7 @@
>>   *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
>>   */
>>  #include "sched.h"
>> +#include "thermal.h"
>>  
>>  #include <trace/events/sched.h>
>>  
>> @@ -7574,6 +7575,8 @@ static void update_blocked_averages(int cpu)
>>  		done = false;
>>  
>>  	update_blocked_load_status(rq, !done);
>> +
>> +	trigger_thermal_pressure_average(rq);
>>  	rq_unlock_irqrestore(rq, &rf);
>>  }
> 
> This changes only 1 of the 2 implementations of
> update_blocked_averages(). Also, how does this interact with
> rq->has_blocked_load ?
I will add it to the other implementation of update_blocked_averages and
will also update others_have_blocked.
> 
>> @@ -9933,6 +9936,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
>>  
>>  	update_misfit_status(curr, rq);
>>  	update_overutilized_status(task_rq(curr));
>> +
>> +	trigger_thermal_pressure_average(rq);
>>  }
> 
> This seems to imply all this thermal stuff is fair only, in which case I
> could suggest putting those few lines in fair.c. ~45 extra lines on
> 1e5+ lines really doesn't matter.
> 


-- 
Warm Regards
Thara