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From: Parth Shah <parth@linux.ibm.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@redhat.com,
	vincent.guittot@linaro.org, patrick.bellasi@matbug.net,
	qais.yousef@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
Subject: Re: [RFC 0/3] Introduce per-task latency_tolerance for scheduler hints
Date: Thu, 5 Dec 2019 22:43:44 +0530	[thread overview]
Message-ID: <5c5b61fa-e8f7-5aa7-0fe0-91cb0d4736fb@linux.ibm.com> (raw)
In-Reply-To: <838f233e-fa4c-d5a3-9b50-69e2e121edda@arm.com>



On 12/5/19 7:33 PM, Dietmar Eggemann wrote:
> On 05/12/2019 11:49, Valentin Schneider wrote:
>>  
>> On 05/12/2019 09:24, Dietmar Eggemann wrote:
>>> On 25/11/2019 10:46, Parth Shah wrote:
>>>> This patch series is based on the discussion started as the "Usecases for
>>>> the per-task latency-nice attribute"[1]
>>>>
>>>> This patch series introduces a new per-task attribute latency_tolerance to
>>>> provide the scheduler hints about the latency requirements of the task.
>>>
>>> I forgot but is there a chance to have this as a per-taskgroup attribute
>>> as well?
>>>
>>
>> Peter argued we should go for task attributes first, and then
>> cgroup/taskgroups later on:
>>
>> https://lore.kernel.org/lkml/20190905083127.GA2332@hirez.programming.kicks-ass.net/
> 
> OK, I went through this thread again. So Google or we have to provide
> the missing per-taskgroup API via cpu controller's attributes (like for
> uclamp) for the EAS usecase.

I suppose many others (including myself) will also be interested in having
per-taskgroup attribute via CPU controller.

> 
> After reading:
> 
> https://lore.kernel.org/r/20190905114030.GL2349@hirez.programming.kicks-ass.net
> 
> IMHO the following mapping of the existing Android (binary)
> latency_sensitive per-taskgroup flag makes sense:
> 
> latency_sensitive=1 -> latency_tolerance*[-20 .. -1] (less tolerant,
> more sensitive)
> 
> latency_sensitive=0 -> latency_tolerance[0 .. 19] (more tolerant, less
> sensitive)
> 
> Default value is 0 so not latency_sensitive.
> 
> * Since we use [-20 .. 19] as values for latency_tolerance we could name
> it latency_nice. It's shorter ... ?

I kept choosing appropriate name and possible values for this new attribute
in the separate thread. https://lkml.org/lkml/2019/9/30/215
From which discussion, looking at Patrick's comment
https://lkml.org/lkml/2019/9/18/678 I thought of picking latency_tolerance
as the appropriate name.
Still will be happy to change as per the community needs.

Thanks,
parth


  reply	other threads:[~2019-12-05 17:14 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-25  9:46 [RFC 0/3] Introduce per-task latency_tolerance for scheduler hints Parth Shah
2019-11-25  9:46 ` [RFC 1/3] Introduce latency-tolerance as an per-task attribute Parth Shah
2019-12-03  8:36   ` Qais Yousef
2019-12-03 15:47     ` Parth Shah
2019-12-05  9:24       ` Dietmar Eggemann
2019-12-05 11:42         ` Parth Shah
2019-11-25  9:46 ` [RFC 2/3] Propagate parent task's latency requirements to the child task Parth Shah
2019-11-25  9:46 ` [RFC 3/3] Allow sched_{get,set}attr to change latency_tolerance of the task Parth Shah
2019-12-03  8:39   ` Qais Yousef
2019-12-03 15:51     ` Parth Shah
2019-12-05  9:24       ` Dietmar Eggemann
2019-12-06 16:04         ` Dietmar Eggemann
2019-12-08  5:52           ` Parth Shah
2019-12-05  9:24 ` [RFC 0/3] Introduce per-task latency_tolerance for scheduler hints Dietmar Eggemann
2019-12-05 10:49   ` Valentin Schneider
2019-12-05 14:03     ` Dietmar Eggemann
2019-12-05 17:13       ` Parth Shah [this message]
2019-12-06 12:31         ` Dietmar Eggemann
2019-12-08  5:57           ` Parth Shah

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