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Date: Fri, 28 Oct 2016 09:29:49 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Vikram Mulukutla <markivx@codeaurora.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Srivatsa Vaddagiri <vatsa@codeaurora.org>,
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        Leo Yan <leo.yan@linaro.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Vikram Mulukutla <markivx@codeauorora.org>
Subject: Re: [RFC PATCH 0/3] sched: Introduce Window Assisted Load Tracking
Message-ID: <20161028072949.GQ3102@twins.programming.kicks-ass.net>
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On Fri, Oct 28, 2016 at 12:10:39AM -0700, Vikram Mulukutla wrote:
> 
> We propose Window-Assisted Load Tracking (WALT) as an alternative or additional
> load tracking scheme in lieu of or along with PELT, one that in our estimation
> better tracks task demand and CPU utilization especially for use cases on
> mobile devices. WALT was conceived by Srivatsa Vaddagiri to provide better
> perf-per-watt numbers on asymmetric CPU (frequency and/or IPC) implementations,
> (specifically on Qualcomm Snapgdragon chipsets running Android) and its metrics
> have been used to guide task placement and p-state selection (load balancing
> in CFS still uses PELT statistics). WALT is now present in the android-common
> kernel as well. 

And how come we only learn of it after its already shipping? Isn't that
arse backwards?