Re: [PATCH v2 8/8] sched/pelt: Introduce PELT multiplier

From: Vincent Guittot <vincent.guittot@linaro.org>
To: Ashay Jaiswal <quic_ashayj@quicinc.com>
Cc: Qais Yousef <qyousef@layalina.io>, Ingo Molnar <mingo@kernel.org>,
	 Peter Zijlstra <peterz@infradead.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	 Viresh Kumar <viresh.kumar@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	 linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	 Lukasz Luba <lukasz.luba@arm.com>, Wei Wang <wvw@google.com>,
	Rick Yiu <rickyiu@google.com>,
	 Chung-Kai Mei <chungkai@google.com>,
	quic_anshar@quicinc.com, quic_atulpant@quicinc.com,
	 quic_shashim@quicinc.com, quic_rgottimu@quicinc.com,
	 quic_adharmap@quicinc.com, quic_kshivnan@quicinc.com,
	 quic_pkondeti@quicinc.com
Subject: Re: [PATCH v2 8/8] sched/pelt: Introduce PELT multiplier
Date: Tue, 30 Jan 2024 18:28:40 +0100	[thread overview]
Message-ID: <CAKfTPtB=nv7DDqTvsdenOg+UNoNFx=f2SLvihHx+CMkeE6NyNA@mail.gmail.com> (raw)
In-Reply-To: <8dfb5db7-6da0-4f6f-30ef-8966428e4a1c@quicinc.com>

On Sun, 28 Jan 2024 at 17:22, Ashay Jaiswal <quic_ashayj@quicinc.com> wrote:
>
> Hello Qais Yousef,
>
> Thank you for your response.
>
> On 1/21/2024 5:34 AM, Qais Yousef wrote:
> > Hi Ashay
> >
> > On 01/20/24 13:22, Ashay Jaiswal wrote:
> >> Hello Qais Yousef,
> >>
> >> We ran few benchmarks with PELT multiplier patch on a Snapdragon 8Gen2
> >> based internal Android device and we are observing significant
> >> improvements with PELT8 configuration compared to PELT32.
> >>
> >> Following are some of the benchmark results with PELT32 and PELT8
> >> configuration:
> >>
> >> +-----------------+---------------+----------------+----------------+
> >> | Test case                       |     PELT32     |     PELT8      |
> >> +-----------------+---------------+----------------+----------------+
> >> |                 |    Overall    |     711543     |     971275     |
> >> |                 +---------------+----------------+----------------+
> >> |                 |    CPU        |     193704     |     224378     |
> >> |                 +---------------+----------------+----------------+
> >> |ANTUTU V9.3.9    |    GPU        |     284650     |     424774     |
> >> |                 +---------------+----------------+----------------+
> >> |                 |    MEM        |     125207     |     160548     |
> >> |                 +---------------+----------------+----------------+
> >> |                 |    UX         |     107982     |     161575     |
> >> +-----------------+---------------+----------------+----------------+
> >> |                 |   Single core |     1170       |     1268       |
> >> |GeekBench V5.4.4 +---------------+----------------+----------------+
> >> |                 |   Multi core  |     2530       |     3797       |
> >> +-----------------+---------------+----------------+----------------+
> >> |                 |    Twitter    |     >50 Janks  |     0          |
> >> |     SCROLL      +---------------+----------------+----------------+
> >> |                 |    Contacts   |     >30 Janks  |     0          |
> >> +-----------------+---------------+----------------+----------------+
> >>
> >> Please let us know if you need any support with running any further
> >> workloads for PELT32/PELT8 experiments, we can help with running the
> >> experiments.
> >
> > Thanks a lot for the test results. Was this tried with this patch alone or
> > the whole series applied?
> >
> I have only applied patch8(sched/pelt: Introduce PELT multiplier) for the tests.
>
> > Have you tried to tweak each policy response_time_ms introduced in patch
> > 7 instead? With the series applied, boot with PELT8, record the response time
> > values for each policy, then boot back again to PELT32 and use those values.
> > Does this produce similar results?
> >
> As the device is based on 5.15 kernel, I will try to pull all the 8 patches
> along with the dependency patches on 5.15 and try out the experiments as
> suggested.

Generally speaking, it would be better to compare with the latest
kernel or at least close and which includes new features added since
v5.15 (which is more than 2 years old now). I understand that this is
not always easy or doable but you could be surprised by the benefit of
some features like [0] merged since v5.15

[0] https://lore.kernel.org/lkml/249816c9-c2b5-8016-f9ce-dab7b7d384e4@arm.com/

>
> > You didn't share power numbers which I assume the perf gains are more important
> > than the power cost for you.
> >
> If possible I will try to collect the power number for future test and share the
> details.
>
> >
> > Thanks!
> >
> > --
> > Qais Yousef