From: Willy Wolff <willy.mh.wolff.ml@gmail.com>
To: Lukasz Luba <lukasz.luba@arm.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>,
k.konieczny@samsung.com, krzk@kernel.org, kgene@kernel.org,
s.nawrocki@samsung.com, b.zolnierkie@samsung.com,
chanwoo@kernel.org, myungjoo.ham@samsung.com,
kyungmin.park@samsung.com, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 0/2] PM / devfreq: Add delayed timer for polling
Date: Fri, 10 Jul 2020 17:12:33 +0200 [thread overview]
Message-ID: <20200710151233.ci5c4rgwb64eswy7@macmini.local> (raw)
In-Reply-To: <a3339c58-6350-9298-6053-9dc021170048@arm.com>
Hi Lukasz,
On 2020-07-08-15-25-03, Lukasz Luba wrote:
> Hi Willy,
>
> On 7/3/20 1:33 PM, Willy Wolff wrote:
> > Hi Chanwoo,
> >
> > I think it doesn't help on the benchmark I suggested that is doing only memory
> > accesses. With both timer, I have the same timing.
> >
> > To test the benchmark with these new patches about timer:
> >
> > git clone https://github.com/wwilly/benchmark.git \
> > && cd benchmark \
> > && source env.sh \
> > && ./bench_build.sh \
> > && bash source/scripts/test_dvfs_mem_patched.sh
> >
> > The benchmark is set by default to run for 1s, but you can increase this by
> > tweaking the script as:
> >
> > taskset 8 ./bench_install/bin/microbe_cache 33554431 0 9722222 <TIME in sec> ${little_freq}
> >
> >
> > Also, as I reported the issue, would it be possible to add a
> > Reported-by: Willy Wolff <willy.mh.wolff.ml@gmail.com> ?
> > Many thanks in advance.
>
> Thank you for your good work and the benchmark. I hope you will continue
> to use it and report some issues. I am going to send a follow up patches
> for the DMC and I will add your 'Reported-by'. In the tests I can see
> the improvements, but it's worth to consult with you if I understand
> the new results correctly.
>
Thanks for that. I will follow on the other patch thread discussion.
> I think there is still some area for improvements in the devfreq and you
> could find the interesting bits to contribute.
In fact, this benchmark is motivated about part of my PhD research that has just
been accepted at LCTES2020: "Performance Optimization on big.LITTLE Architectures:
A Memory-latency Aware Approach" at https://dl.acm.org/doi/10.1145/3372799.3394370
Basically, it's about snooping latency with "bad" CPU DVFS choice on big.LITTLE
systems or more generally SMP/AMP architecture. I'm cleaning up my code and will
propose patches as an RFC later. It introduces a new CPU DVFS governor to limit
snooping latency.
Cheers,
Willy
>
> Regards,
> Lukasz
>
> >
> >
> > Best Regards,
> > Willy
> >
next prev parent reply other threads:[~2020-07-10 15:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200703061508epcas1p171aa3c0ab832b77e5837d8bd1e563742@epcas1p1.samsung.com>
2020-07-03 6:26 ` [RFC PATCH 0/2] PM / devfreq: Add delayed timer for polling Chanwoo Choi
[not found] ` <CGME20200703061509epcas1p10446471df6497b4b2d7066280daa7f87@epcas1p1.samsung.com>
2020-07-03 6:26 ` [RFC PATCH 1/2] PM / devfreq: Add support delayed timer for polling mode Chanwoo Choi
[not found] ` <CGME20200703061509epcas1p3e338b614c44f5d8b566dae92f11cc8cb@epcas1p3.samsung.com>
2020-07-03 6:26 ` [RFC PATCH 2/2] memory: samsung: exynos5422-dmc: Use delayed timer as default Chanwoo Choi
2020-07-08 12:33 ` Krzysztof Kozlowski
2020-07-09 5:44 ` Chanwoo Choi
2020-07-03 12:33 ` [RFC PATCH 0/2] PM / devfreq: Add delayed timer for polling Willy Wolff
2020-07-08 14:25 ` Lukasz Luba
2020-07-10 15:12 ` Willy Wolff [this message]
2020-07-13 8:55 ` Lukasz Luba
2020-07-08 10:52 ` Bartlomiej Zolnierkiewicz
2020-07-08 14:01 ` Lukasz Luba
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