linux-kernel - Re: [RFC 0/2] Optimize the idle CPU search

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Message-Id: <c57434ff-b939-cd93-de93-11435345b2ac@linux.ibm.com>
Date:   Mon, 8 Jul 2019 14:39:38 +0530
From:   Parth Shah <parth@...ux.ibm.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, mingo@...hat.com,
        vincent.guittot@...aro.org, subhra.mazumdar@...cle.com
Subject: Re: [RFC 0/2] Optimize the idle CPU search



On 7/8/19 1:38 PM, Peter Zijlstra wrote:
> On Mon, Jul 08, 2019 at 10:24:30AM +0530, Parth Shah wrote:
>> When searching for an idle_sibling, scheduler first iterates to search for
>> an idle core and then for an idle CPU. By maintaining the idle CPU mask
>> while iterating through idle cores, we can mark non-idle CPUs for which
>> idle CPU search would not have to iterate through again. This is especially
>> true in a moderately load system
>>
>> Optimize idle CPUs search by marking already found non idle CPUs during
>> idle core search. This reduces iteration count when searching for idle
>> CPUs, resulting in lower iteration count.
> 
> Have you seen these patches:
> 
>   https://lkml.kernel.org/r/20180530142236.667774973@infradead.org
> 
> I've meant to get back to that, but never quite had the time :/
> 

Ok, I was not aware of this patch-set.
It seems interesting and I will evaluate it.


Thanks