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From: Lukasz Luba <lukasz.luba@arm.com>
To: Vincent Donnefort <vdonnefort@google.com>
Cc: linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com,
	morten.rasmussen@arm.com, chris.redpath@arm.com,
	qperret@google.com, tao.zhou@linux.dev, kernel-team@android.com,
	peterz@infradead.org, mingo@redhat.com,
	vincent.guittot@linaro.org
Subject: Re: [PATCH v10 0/7] feec() energy margin removal
Date: Thu, 9 Jun 2022 13:53:22 +0100	[thread overview]
Message-ID: <6099583c-c986-e1f3-1eee-33b504286757@arm.com> (raw)
In-Reply-To: <20220607123254.565579-1-vdonnefort@google.com>

Hi Vincent,

On 6/7/22 13:32, Vincent Donnefort wrote:
> Hi,
> 
> Here's a new version of the patch-set to get rid of the energy margin in
> feec(). Many thanks to all for the insightful comments I got.
> 
> find_energy_efficient() (feec()) will migrate a task to save energy only if
> it saves at least 6% of the total energy consumed by the system. This
> conservative approach is a problem on a system where a lot of small tasks
> create a huge load on the overall: very few of them will be allowed to
> migrate to a smaller CPU, wasting a lot of energy. Instead of trying to
> determine yet another margin, let's try to remove it.
> 
> The first elements of this patch-set are various fixes and improvement that
> stabilizes task_util and ensures energy comparison fairness across all CPUs
> of the topology. Only once those fixed, we can completely remove the margin
> and let feec() aggressively place task and save energy.
> 

I've run this patch set on pixel6 (android-mainline) and gathered energy
values from the meter during the PCmark 3.0.

It looks good, with these patches we have ~10% lower energy usage and
only ~3% lower score.

There are no other issues, everything works fine. Feel free to add:

Tested-by: Lukasz Luba <lukasz.luba@arm.com>

to the whole patch set.

Regards,
Lukasz

  parent reply	other threads:[~2022-06-09 12:54 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-07 12:32 [PATCH v10 0/7] feec() energy margin removal Vincent Donnefort
2022-06-07 12:32 ` [PATCH v10 1/7] sched/fair: Provide u64 read for 32-bits arch helper Vincent Donnefort
2022-06-09 15:23   ` Tao Zhou
2022-06-14 11:45     ` Vincent Donnefort
2022-06-14 14:28       ` Tao Zhou
2022-06-21  8:32         ` Vincent Donnefort
2022-06-07 12:32 ` [PATCH v10 2/7] sched/fair: Decay task PELT values during wakeup migration Vincent Donnefort
2022-06-08  9:53   ` Dietmar Eggemann
2022-06-11 13:56   ` Tao Zhou
2022-06-07 12:32 ` [PATCH v10 3/7] sched, drivers: Remove max param from effective_cpu_util()/sched_cpu_util() Vincent Donnefort
2022-06-07 12:32 ` [PATCH v10 4/7] sched/fair: Rename select_idle_mask to select_rq_mask Vincent Donnefort
2022-06-07 12:32 ` [PATCH v10 5/7] sched/fair: Use the same cpumask per-PD throughout find_energy_efficient_cpu() Vincent Donnefort
2022-06-07 12:32 ` [PATCH v10 6/7] sched/fair: Remove task_util from effective utilization in feec() Vincent Donnefort
2022-06-07 12:32 ` [PATCH v10 7/7] sched/fair: Remove the energy margin " Vincent Donnefort
2022-06-09 12:53 ` Lukasz Luba [this message]
2022-06-14 11:47   ` [PATCH v10 0/7] feec() energy margin removal Vincent Donnefort

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