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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Steve Muckle <steve.muckle@linaro.org>
Cc: Linux PM list <linux-pm@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Juri Lelli <juri.lelli@arm.com>, Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC][PATCH 6/7] cpufreq: schedutil: Add iowait boosting
Date: Wed, 03 Aug 2016 01:03:23 +0200	[thread overview]
Message-ID: <1808398.B5hOCmgoWi@vostro.rjw.lan> (raw)
In-Reply-To: <20160802013531.GC9332@graphite.smuckle.net>

On Monday, August 01, 2016 06:35:31 PM Steve Muckle wrote:
> On Mon, Aug 01, 2016 at 01:37:59AM +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > 
> > Modify the schedutil cpufreq governor to boost the CPU frequency
> > if the UUF_IO flag is passed to it via cpufreq_update_util().
> > 
> > If that happens, the frequency is set to the maximum during
> > the first update after receiving the UUF_IO flag and then the
> > boost is reduced by half during each following update.
> 
> Were these changes to schedutil part of the positive test results
> mentioned in patch 5? Or are those just from intel pstate?
> 
> I was nervous about the effect of this on power and tested a couple low
> power usecases. The platform is the Hikey 96board (8 core ARM A53,
> single CPUfreq domain) running AOSP Android and schedutil backported to
> kernel 4.4. These tests run mp3 and mpeg4 playback for a little while,
> recording total energy consumption during the test along with frequency
> residency.
> 
> As the results below show I did not measure an appreciable effect - if
> anything things may be slightly better with the patches.
> 
> The hardcoding of a non-tunable boosting scheme makes me nervous but
> perhaps it could be revisited if some platform or configuration shows
> a noticeable regression?

That would be my approach. :-)

I'm not a big fan of tunables in general, as there are only a few people
who actually set them to anything different from the default and then they
get a lot of focus (even though they are after super-corner cases sometimes).

Thanks,
Rafael

  reply	other threads:[~2016-08-02 22:58 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-31 23:31 [RFC][PATCH 0/7] cpufreq / sched: cpufreq_update_util() flags and iowait boosting Rafael J. Wysocki
2016-07-31 23:34 ` [RFC][PATCH 1/7] cpufreq / sched: Make schedutil access utilization data directly Rafael J. Wysocki
2016-08-01 19:28   ` Steve Muckle
2016-08-01 23:46     ` Rafael J. Wysocki
2016-08-02 10:38       ` Juri Lelli
2016-08-02 14:28         ` Steve Muckle
2016-08-02 14:43           ` Juri Lelli
2016-08-08 10:38       ` Peter Zijlstra
2016-07-31 23:35 ` [RFC][PATCH 2/7] cpufreq / sched: Drop cpufreq_trigger_update() Rafael J. Wysocki
2016-07-31 23:36 ` [RFC][PATCH 3/7] cpufreq / sched: Check cpu_of(rq) in cpufreq_update_util() Rafael J. Wysocki
2016-08-01  7:29   ` Dominik Brodowski
2016-08-01 14:57     ` Rafael J. Wysocki
2016-08-01 19:48     ` Steve Muckle
2016-08-01 23:43       ` Rafael J. Wysocki
2016-07-31 23:36 ` [RFC][PATCH 4/7] cpufreq / sched: Add flags argument to cpufreq_update_util() Rafael J. Wysocki
2016-08-01  7:33   ` Dominik Brodowski
2016-08-01 14:57     ` Rafael J. Wysocki
2016-08-01 19:59       ` Steve Muckle
2016-08-01 23:44         ` Rafael J. Wysocki
2016-08-02  1:36           ` Steve Muckle
2016-07-31 23:37 ` [RFC][PATCH 5/7] cpufreq / sched: UUF_IO flag to indicate iowait condition Rafael J. Wysocki
2016-08-02  1:22   ` Steve Muckle
2016-08-02  1:37     ` Rafael J. Wysocki
2016-08-02 22:02       ` Steve Muckle
2016-08-02 22:38         ` Rafael J. Wysocki
2016-08-04  2:24           ` Steve Muckle
2016-08-04 21:19             ` Rafael J. Wysocki
2016-08-04 22:09               ` Steve Muckle
2016-08-05 23:36                 ` Rafael J. Wysocki
2016-07-31 23:37 ` [RFC][PATCH 6/7] cpufreq: schedutil: Add iowait boosting Rafael J. Wysocki
2016-08-02  1:35   ` Steve Muckle
2016-08-02 23:03     ` Rafael J. Wysocki [this message]
2016-07-31 23:38 ` [RFC][PATCH 7/7] cpufreq: intel_pstate: Change P-state selection algorithm for Core Rafael J. Wysocki
2016-08-04  4:18   ` Doug Smythies
2016-08-04  6:53   ` Doug Smythies
2016-08-06  0:02     ` Rafael J. Wysocki
2016-08-09 17:16       ` Doug Smythies
2016-08-13 15:59       ` Doug Smythies
2016-08-19 14:47         ` Peter Zijlstra
2016-08-20  1:06           ` Rafael J. Wysocki
2016-08-20  6:40           ` Doug Smythies
2016-08-22 18:53         ` Srinivas Pandruvada
2016-08-22 22:53           ` Doug Smythies
2016-08-23  3:48   ` Wanpeng Li
2016-08-23  4:08     ` Srinivas Pandruvada
2016-08-23  4:50       ` Wanpeng Li
2016-08-23 17:30         ` Rafael J. Wysocki
2016-08-01 15:26 ` [RFC][PATCH 0/7] cpufreq / sched: cpufreq_update_util() flags and iowait boosting Doug Smythies
2016-08-01 16:30   ` Rafael J. Wysocki
2016-08-08 11:08     ` Peter Zijlstra
2016-08-08 13:01       ` Rafael J. Wysocki

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