linux-kernel - Re: [RFC PATCH 1/1] sched: Extend cpu idle state for 1ms

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Date:   Thu, 3 Aug 2023 16:12:57 -0400
From:   Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To:     Swapnil Sapkal <Swapnil.Sapkal@....com>,
        Shrikanth Hegde <sshegde@...ux.vnet.ibm.com>
Cc:     linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Valentin Schneider <vschneid@...hat.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Aaron Lu <aaron.lu@...el.com>, x86@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 1/1] sched: Extend cpu idle state for 1ms

On 8/3/23 01:53, Swapnil Sapkal wrote:
[...]

Those are interesting metrics. I still have no clue why it behaves that 
way though.

More specifically: I also noticed that the number of migrations is 
heavily affected, and that select_task_rq behavior changes drastically. 
I'm unsure why though.

> 
> Can you share your build config just in case I am missing something.

Build config attached.

Thanks,

Mathieu

> 
>>
>> And using it now brings the hackbench wall time at 28s :)
>>
>> Thanks,
>>
>> Mathieu
>>
>>>
>>>>>>        struct task_struct    *stop;
>>>>>>        unsigned long        next_balance;
>>>>>>        struct mm_struct    *prev_mm;
>>>>
>>
> -- 
> Thanks and regards,
> Swapnil

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com

View attachment "config-hackbench-test" of type "text/plain" (277082 bytes)