linux-kernel - Re: [PATCH] sched: Introduce scaled capacity awareness in enqueue

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Message-ID: <f0805f09-b30f-9071-6c97-553597f3205c@oracle.com>
Date:   Fri, 2 Jun 2017 11:20:20 -0700
From:   Rohit Jain <rohit.k.jain@...cle.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, mingo@...hat.com,
        vincent.guittot@...aro.org, morten.rasmussen@....com,
        dietmar.eggemann@....com, Dhaval Giani <dhaval.giani@...cle.com>
Subject: Re: [PATCH] sched: Introduce scaled capacity awareness in enqueue

On 06/01/2017 05:37 AM, Peter Zijlstra wrote:
> On Thu, Jun 01, 2017 at 02:28:27PM +0200, Peter Zijlstra wrote:
>> On Wed, May 31, 2017 at 03:19:46PM -0700, Rohit Jain wrote:
>>
>>>>> 2) This scaled capacity is normalized and mapped into buckets.
>>>> Why?
> And its not at all clear why you'd need
> that to begin with.

Here is the problem I am trying to solve:

The benchmark(s) have a high degree of variance when run multiple
times.

We believe it is because of the scheduler not being aware of the scaled
down capacity of the CPUs because of IRQ/RT activity.

This patch helps in solving the above problem. Do you have any thoughts
on solving this problem in any other way?