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Date:   Thu, 20 Feb 2020 19:00:40 +0100
From:   Krzysztof Kozlowski <krzk@kernel.org>
To:     Lukasz Luba <lukasz.luba@arm.com>
Cc:     linux-kernel@vger.kernel.org, kgene@kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org,
        linux-pm@vger.kernel.org, myungjoo.ham@samsung.com,
        kyungmin.park@samsung.com, cw00.choi@samsung.com,
        robh+dt@kernel.org, mark.rutland@arm.com, b.zolnierkie@samsung.com,
        dietmar.eggemann@arm.com
Subject: Re: [RESEND PATCH v2 0/2] Enable Odroid-XU3/4 to use Energy Model
 and Energy Aware Scheduler
Message-ID: <20200220180040.GA8338@kozik-lap>
References: <20200220095636.29469-1-lukasz.luba@arm.com>
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On Thu, Feb 20, 2020 at 09:56:34AM +0000, Lukasz Luba wrote:
> Hi all,
> 
> This is just a resend, now with proper v2 in the patches subject.
> 
> The Odroid-XU4/3 is a decent and easy accessible ARM big.LITTLE platform,
> which might be used for research and development.
> 
> This small patch set provides possibility to run Energy Aware Scheduler (EAS)
> on Odroid-XU4/3 and experiment with it. 
> 
> The patch 1/2 provides 'dynamic-power-coefficient' in CPU DT nodes, which is
> then used by the Energy Model (EM).
> The patch 2/2 enables SCHED_MC (which adds another level in scheduling domains)
> and enables EM making EAS possible to run (when schedutil is set as a CPUFreq
> governor).
> 
> 1. Test results
> 
> Two types of different tests have been executed. The first is energy test
> case showing impact on energy consumption of this patch set. It is using a
> synthetic set of tasks (rt-app based). The second is the performance test
> case which is using hackbench (less time to complete is better).
> In both tests schedutil has been used as cpufreq governor. In all tests
> PROVE_LOCKING has not been compiled into the kernels.
> 
> 1.1 Energy test case
> 
> 10 iterations of 24 periodic rt-app tasks (16ms period, 10% duty-cycle)
> with energy measurement. The cpufreq governor - schedutil. Unit is Joules.
> The energy is calculated based on hwmon0 and hwmon3 power1_input.
> The goal is to save energy, lower is better.
> 
> +-----------+-----------------+------------------------+
> |           | Without patches | With patches           |
> +-----------+--------+--------+----------------+-------+
> | benchmark |  Mean  | RSD*   | Mean           | RSD*  |
> +-----------+--------+--------+----------------+-------+
> | 24 rt-app |  21.56 |  1.37% |  19.85 (-9.2%) | 0.92% |
> |    tasks  |        |        |                |       |
> +-----------+--------+--------+----------------+-------+
> 
> 1.2 Performance test case
> 
> 10 consecutive iterations of hackbench (hackbench -l 500 -s 4096),
> no delay between two successive executions.
> The cpufreq governor - schedutil. Units in seconds.
> The goal is to see not regression, lower completion time is better.
> 
> +-----------+-----------------+------------------------+
> |           | Without patches | With patches           |
> +-----------+--------+--------+----------------+-------+
> | benchmark | Mean   | RSD*   | Mean           | RSD*  |
> +-----------+--------+--------+----------------+-------+
> | hackbench |  8.15  | 2.86%  |  7.95 (-2.5%)  | 0.60% |
> +-----------+--------+--------+----------------+-------+
> 
> *RSD: Relative Standard Deviation (std dev / mean)

Nice measurements!

Applied both, thank you.

Best regards,
Krzysztof