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Re: [PATCH 3/6] cpufreq: schedutil: ensure max frequency while running RT/DL tasks

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On 02-03-17, 15:45, Patrick Bellasi wrote:
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> @@ -293,15 +305,29 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
>  	if (curr == sg_policy->thread)
>  		goto done;
>  
> +	/*
> +	 * While RT/DL tasks are running we do not want FAIR tasks to
> +	 * overwrite this CPU's flags, still we can update utilization and
> +	 * frequency (if required/possible) to be fair with these tasks.
> +	 */
> +	rt_mode = task_has_dl_policy(curr) ||
> +		  task_has_rt_policy(curr) ||
> +		  (flags & SCHED_CPUFREQ_RT_DL);
> +	if (rt_mode)
> +		sg_cpu->flags |= flags;
> +	else
> +		sg_cpu->flags = flags;

This looks so hacked up :)

Wouldn't it be better to let the scheduler tell us what all kind of tasks it has
in the rq of a CPU and pass a mask of flags? I think it wouldn't be difficult
(or time consuming) for the scheduler to know that, but I am not 100% sure.

IOW, the flags field in cpufreq_update_util() will represent all tasks in the
rq, instead of just the task that is getting enqueued/dequeued..

And obviously we need to get some utilization numbers for the RT and DL tasks
going forward, switching to max isn't going to work for ever :)

-- 
viresh

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[PATCH 0/6] cpufreq: schedutil: fixes for flags updates Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-02 16:50 +0100
  [PATCH 3/6] cpufreq: schedutil: ensure max frequency while running RT/DL tasks Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-02 16:50 +0100
    Re: [PATCH 3/6] cpufreq: schedutil: ensure max frequency while  running RT/DL tasks Viresh Kumar <viresh.kumar@linaro.org> - 2017-03-03 10:00 +0100
      Re: [PATCH 3/6] cpufreq: schedutil: ensure max frequency while  running RT/DL tasks Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-03 13:50 +0100
  [PATCH 5/6] cpufreq: schedutil: avoid utilisation update when not necessary Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-02 17:00 +0100
  [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for frequencies selections Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-02 17:00 +0100
    Re: [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for  frequencies selections Viresh Kumar <viresh.kumar@linaro.org> - 2017-03-03 07:30 +0100
      Re: [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for  frequencies selections Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-03 14:20 +0100
        Re: [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for  frequencies selections Viresh Kumar <viresh.kumar@linaro.org> - 2017-03-06 06:20 +0100
    Re: [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for  frequencies selections Steven Rostedt <rostedt@goodmis.org> - 2017-03-06 15:40 +0100
  [PATCH 6/6] sched/rt: fast switch to maximum frequency when RT tasks are scheduled Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-02 17:00 +0100
  Re: [PATCH 0/6] cpufreq: schedutil: fixes for flags updates Vincent Guittot <vincent.guittot@linaro.org> - 2017-03-02 17:20 +0100
    Re: [PATCH 0/6] cpufreq: schedutil: fixes for flags updates Patrick Bellasi <patrick.bellasi@arm.com> - 2017-03-02 18:40 +0100

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