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Subject: Re: [RFC 1/3] Introduce latency-tolerance as an per-task attribute
To:     Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Qais Yousef <qais.yousef@arm.com>
Cc:     linux-kernel@vger.kernel.org, peterz@infradead.org,
        mingo@redhat.com, vincent.guittot@linaro.org,
        patrick.bellasi@matbug.net, valentin.schneider@arm.com,
        pavel@ucw.cz, dhaval.giani@oracle.com, qperret@qperret.net,
        David.Laight@ACULAB.COM, morten.rasmussen@arm.com, pjt@google.com,
        tj@kernel.org, viresh.kumar@linaro.org, rafael.j.wysocki@intel.com,
        daniel.lezcano@linaro.org
References: <20191125094618.30298-1-parth@linux.ibm.com>
 <20191125094618.30298-2-parth@linux.ibm.com>
 <20191203083654.3ctttimdiujdt7tl@e107158-lin.cambridge.arm.com>
 <59044b60-a7d8-9508-4975-06afdcfd33cd@linux.ibm.com>
 <d6a1d7ae-fe5e-7f52-60b5-4daac9a70107@arm.com>
From:   Parth Shah <parth@linux.ibm.com>
Date:   Thu, 5 Dec 2019 17:12:15 +0530
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On 12/5/19 2:54 PM, Dietmar Eggemann wrote:
> On 03/12/2019 16:47, Parth Shah wrote:
>>
>> On 12/3/19 2:06 PM, Qais Yousef wrote:
>>> On 11/25/19 15:16, Parth Shah wrote:
>>>> Latency-tolerance indicates the latency requirements of a task with respect
>>>> to the other tasks in the system. The value of the attribute can be within
>>>> the range of [-20, 19] both inclusive to be in-line with the values just
>>>> like task nice values.
>>>>
>>>> latency_tolerance = -20 indicates the task to have the least latency as
>>>> compared to the tasks having latency_tolerance = +19.
>>>>
>>>> The latency_tolerance may affect only the CFS SCHED_CLASS by getting
>>>> latency requirements from the userspace.
> 
> [...]
> 
>>>> diff --git a/include/linux/sched/latency_tolerance.h b/include/linux/sched/latency_tolerance.h
> 
> Do we really need an extra header file for this? I know there is
> linux/sched/prio.h but couldn't this go into kernel/sched/sched.h?

We can include this in kernel/sched/sched.h itself unless we have any plans
to use it outside the scheduler subsystem. I will then add it as specified
in next revision.

> 
> [...]
>