linux-kernel - Re: Re: [PATCH 2/4] sched/eevdf: Sort the rbtree by virtual deadline

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Message-ID: <917f6c3f-33b6-4161-af30-f8bbd99a8720@bytedance.com>
Date:   Wed, 8 Nov 2023 16:51:32 +0800
From:   Abel Wu <wuyun.abel@...edance.com>
To:     Benjamin Segall <bsegall@...gle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Valentin Schneider <valentin.schneider@....com>,
        Barry Song <21cnbao@...il.com>, Chen Yu <yu.c.chen@...el.com>,
        Daniel Jordan <daniel.m.jordan@...cle.com>,
        "Gautham R . Shenoy" <gautham.shenoy@....com>,
        Joel Fernandes <joel@...lfernandes.org>,
        K Prateek Nayak <kprateek.nayak@....com>,
        Mike Galbraith <efault@....de>,
        Qais Yousef <qyousef@...alina.io>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Yicong Yang <yangyicong@...wei.com>,
        Youssef Esmat <youssefesmat@...omium.org>,
        linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH 2/4] sched/eevdf: Sort the rbtree by virtual deadline

On 11/8/23 7:26 AM, Benjamin Segall Wrote:
> Abel Wu <wuyun.abel@...edance.com> writes:
> 
>> Sort the task timeline by virtual deadline and keep the min_vruntime
>> in the augmented tree, so we can avoid doubling the worst case cost
>> and make full use of the cached leftmost node to enable O(1) fastpath
>> picking in next patch.
>>
>> This patch also cleans up the unused max_vruntime() and adjusts pos
>> for some functions.
>>
>> Signed-off-by: Abel Wu <wuyun.abel@...edance.com>
>> ---
> 
> I've run this through my tester and it agrees that it does fulfil the
> EEVDF pick (though this implementation is trivial enough that that's
> fairly obvious just by reading the code, which is a nice bonus upgrade).
> 
> And it makes sense that this would help for performance, and the
> fastpath seems likely to trigger most of the time for even better
> results.

Thanks, Benjamin!