From: Willy Wolff <willy.mh.wolff.ml@gmail.com>
To: Chanwoo Choi <cw00.choi@samsung.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Kukjin Kim <kgene@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
linux-pm@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: brocken devfreq simple_ondemand for Odroid XU3/4?
Date: Tue, 23 Jun 2020 18:47:33 +0200 [thread overview]
Message-ID: <20200623164733.qbhua7b6cg2umafj@macmini.local> (raw)
Hi everybody,
Is DVFS for memory bus really working on Odroid XU3/4 board?
Using a simple microbenchmark that is doing only memory accesses, memory DVFS
seems to not working properly:
The microbenchmark is doing pointer chasing by following index in an array.
Indices in the array are set to follow a random pattern (cutting prefetcher),
and forcing RAM access.
git clone https://github.com/wwilly/benchmark.git \
&& cd benchmark \
&& source env.sh \
&& ./bench_build.sh \
&& bash source/scripts/test_dvfs_mem.sh
Python 3, cmake and sudo rights are required.
Results:
DVFS CPU with performance governor
mem_gov = simple_ondemand at 165000000 Hz in idle, should be bumped when the
benchmark is running.
- on the LITTLE cluster it takes 4.74308 s to run (683.004 c per memory access),
- on the big cluster it takes 4.76556 s to run (980.343 c per moemory access).
While forcing DVFS memory bus to use performance governor,
mem_gov = performance at 825000000 Hz in idle,
- on the LITTLE cluster it takes 1.1451 s to run (164.894 c per memory access),
- on the big cluster it takes 1.18448 s to run (243.664 c per memory access).
The kernel used is the last 5.7.5 stable with default exynos_defconfig.
Cheers,
Willy
next reply other threads:[~2020-06-23 16:47 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 16:47 Willy Wolff [this message]
2020-06-23 19:02 ` brocken devfreq simple_ondemand for Odroid XU3/4? Krzysztof Kozlowski
2020-06-23 19:11 ` Krzysztof Kozlowski
2020-06-24 8:01 ` Willy Wolff
2020-06-24 8:14 ` Krzysztof Kozlowski
2020-06-24 8:52 ` Willy Wolff
2020-06-24 10:32 ` Lukasz Luba
2020-06-24 11:18 ` Kamil Konieczny
2020-06-24 12:06 ` Krzysztof Kozlowski
2020-06-24 13:03 ` Lukasz Luba
2020-06-24 13:13 ` Krzysztof Kozlowski
2020-06-24 13:42 ` Lukasz Luba
2020-06-24 15:11 ` Sylwester Nawrocki
2020-06-25 10:02 ` Lukasz Luba
2020-06-25 11:30 ` Kamil Konieczny
2020-06-25 12:02 ` Lukasz Luba
2020-06-25 12:12 ` Kamil Konieczny
2020-06-26 11:22 ` Bartlomiej Zolnierkiewicz
2020-06-29 1:43 ` Chanwoo Choi
2020-06-29 11:52 ` Lukasz Luba
2020-07-01 15:48 ` Willy Wolff
2020-06-29 11:34 ` Lukasz Luba
2020-06-26 17:50 ` Sylwester Nawrocki
2020-06-29 11:41 ` Lukasz Luba
2020-06-29 1:52 ` Chanwoo Choi
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