From: Lukasz Luba <lukasz.luba@arm.com>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: kgene@kernel.org, linux-arm-kernel@lists.infradead.org,
"linux-samsung-soc@vger.kernel.org"
<linux-samsung-soc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
myungjoo.ham@samsung.com, kyungmin.park@samsung.com,
"Chanwoo Choi" <cw00.choi@samsung.com>,
robh+dt@kernel.org, mark.rutland@arm.com,
"Bartłomiej Żołnierkiewicz" <b.zolnierkie@samsung.com>,
dietmar.eggemann@arm.com
Subject: Re: [PATCH 3/3] ARM: exynos_defconfig: Enable Energy Model framework
Date: Wed, 5 Feb 2020 12:49:26 +0000 [thread overview]
Message-ID: <c54e252d-dc55-5fa3-f97f-643d7efbfdc1@arm.com> (raw)
In-Reply-To: <20200131204118.GA27284@kozik-lap>
Hi Krzysztof,
On 1/31/20 8:41 PM, Krzysztof Kozlowski wrote:
> On Fri, Jan 31, 2020 at 05:30:46PM +0000, Lukasz Luba wrote:
>
>>>
>>>> |-----------------------------------------------|---------------
>>>> | performance | SchedUtil | SchedUtil | performance
>>>> | governor | governor | governor | governor
>>>> | | w/o EAS | w/ EAS |
>>>> ----------------|---------------|---------------|---------------|---------------
>>>> hackbench w/ PL | 12.7s | 11.7s | 12.0s | 13.0s - 12.2s
>>>> hackbench w/o PL| 9.2s | 8.1s | 8.2s | 9.2s - 8.4s
>>>
>>> Why does the performance different before and after this patch?
>>
>> Probably due to better locality and cache utilization. I can see that
>> there is ~700k context switches vs ~450k and ~160k migrations vs ~50k.
>> If you need to communicate two threads in different clusters, it will go
>> through CCI.
>
> Mhmm... I was not specific - I mean, "performance governor". All this
> you mentioned should not differ between performance governor before and
> after. However once you have 12.7, then 13.0 - 12.2. Unless multi-core
> scheduler affects it... but then these numbers here are not showing
> only this change, but also the SCHED_MC effect. In such case each of
> commits should be coming with their own numbers.
Agree, I should have not put 'this patch set' in the commit
msg. It should go into the cover letter and avoid this confusion.
You are right with ' Unless multi-core scheduler affects it...',
that's why when the SCHED_MC is missing, the decisions about task
placing might cause this variation and delay '13.0 - 12.2' seconds.
>
>> As mentioned in response to patch 1/3. The fist patch would create MC
>> domain, something different than Energy Model or EAS. The decisions in
>> the scheduler would be different.
>>
>> I can merge 1/3 and 3/3 if you like, though.
>
> I understand now that their independent. Still, they are part of one
> goal to tune the scheduler for Exynos platform. Splitting these looks
> too much, like enabling multiple drivers one after another.
>
> However if you provide numbers for each of cases (before patches, multi
> core scheduler, energy model with DTS), then I see benefit of splitting
> it. Each commit would have its own rationale. I am not sure if it is
> worth such investigation - that's just defconfig... distros might ignore
> it anyway.
Good point, and I agree that it would require more investigation, for
which unfortunately I don't have currently spare cycles.
Should I merge patch 1/3 and 3/3 and send the v2 with a cover letter
which would have the test results?
Regards,
Lukasz
next prev parent reply other threads:[~2020-02-05 12:49 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 21:54 [PATCH 0/3] Enable Odroid-XU3/4 to use Energy Model and Energy Aware Scheduler lukasz.luba
2020-01-27 21:54 ` [PATCH 1/3] ARM: exynos_defconfig: Enable SCHED_MC lukasz.luba
2020-01-31 12:47 ` Krzysztof Kozlowski
2020-01-31 15:59 ` Lukasz Luba
2020-01-31 20:33 ` Krzysztof Kozlowski
2020-01-27 21:54 ` [PATCH 2/3] ARM: dts: exynos: Add Exynos5422 CPU dynamic-power-coefficient information lukasz.luba
2020-01-31 13:05 ` Krzysztof Kozlowski
2020-01-31 16:42 ` Lukasz Luba
2020-01-27 21:54 ` [PATCH 3/3] ARM: exynos_defconfig: Enable Energy Model framework lukasz.luba
2020-01-31 13:16 ` Krzysztof Kozlowski
2020-01-31 17:30 ` Lukasz Luba
2020-01-31 20:41 ` Krzysztof Kozlowski
2020-02-05 12:49 ` Lukasz Luba [this message]
2020-02-06 12:59 ` Krzysztof Kozlowski
2020-02-06 14:15 ` Lukasz Luba
2020-01-31 13:30 ` Bartlomiej Zolnierkiewicz
2020-01-31 13:31 ` Krzysztof Kozlowski
2020-01-31 13:47 ` Bartlomiej Zolnierkiewicz
2020-01-31 13:48 ` Bartlomiej Zolnierkiewicz
2020-01-31 17:38 ` Lukasz Luba
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c54e252d-dc55-5fa3-f97f-643d7efbfdc1@arm.com \
--to=lukasz.luba@arm.com \
--cc=b.zolnierkie@samsung.com \
--cc=cw00.choi@samsung.com \
--cc=devicetree@vger.kernel.org \
--cc=dietmar.eggemann@arm.com \
--cc=kgene@kernel.org \
--cc=krzk@kernel.org \
--cc=kyungmin.park@samsung.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux-samsung-soc@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=myungjoo.ham@samsung.com \
--cc=robh+dt@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).