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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Julia Lawall <julia.lawall@inria.fr>,
	Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@redhat.com>,
	kernel-janitors@vger.kernel.org,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	linux-kernel@vger.kernel.org,
	Gilles Muller <Gilles.Muller@inria.fr>,
	srinivas.pandruvada@linux.intel.com
Subject: Re: default cpufreq gov, was: [PATCH] sched/fair: check for idle core
Date: Tue, 27 Oct 2020 17:18:22 +0530	[thread overview]
Message-ID: <20201027114822.vsh7vpwfnh2tvmpz@vireshk-i7> (raw)
In-Reply-To: <20201027114214.irsgdlfvyo46jpww@e107158-lin>

On 27-10-20, 11:42, Qais Yousef wrote:
> On 10/27/20 11:26, Valentin Schneider wrote:
> > 
> > On 27/10/20 11:11, Qais Yousef wrote:
> > > On 10/22/20 14:02, Peter Zijlstra wrote:
> > >> However I do want to retire ondemand, conservative and also very much
> > >> intel_pstate/active mode. I also have very little sympathy for
> > >> userspace.
> > >
> > > Userspace is useful for testing and sanity checking. Not sure if people use it
> > > to measure voltage/current at each frequency to generate
> > > dynamic-power-coefficient for their platform. Lukasz, Dietmar?
> > >
> > 
> > It's valuable even just for cpufreq sanity checking - we have that test
> > that goes through increasing frequencies and asserts the work done is
> > monotonically increasing. This has been quite useful in the past to detect
> > broken bits.
> > 
> > That *should* still be totally doable with any other governor by using the
> > scaling_{min, max}_freq sysfs interface.
> 
> True. This effectively makes every governor a potential user space governor.
> 
> /me not sure to be happy or grumpy about it

Userspace governor should be kept as is, it is very effective to get
unnecessary governor code out of the path when testing basic
functioning of the hardware/driver. It is quite useful when things
don't work as expected.

-- 
viresh

  reply	other threads:[~2020-10-27 11:48 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 16:37 [PATCH] sched/fair: check for idle core Julia Lawall
2020-10-21  7:29 ` Vincent Guittot
2020-10-21 11:13   ` Peter Zijlstra
2020-10-21 12:27   ` Vincent Guittot
2020-10-21 11:20 ` Mel Gorman
2020-10-21 11:56   ` Julia Lawall
2020-10-21 12:19     ` Peter Zijlstra
2020-10-21 12:42       ` Julia Lawall
2020-10-21 12:52         ` Peter Zijlstra
2020-10-21 13:43           ` Julia Lawall
2020-10-21 18:18           ` Rafael J. Wysocki
2020-10-21 18:15         ` Rafael J. Wysocki
2020-10-21 19:47           ` Julia Lawall
2020-10-21 20:25             ` Rafael J. Wysocki
2020-10-21 13:10       ` Peter Zijlstra
2020-10-21 18:11         ` Rafael J. Wysocki
2020-10-22  4:41           ` Viresh Kumar
2020-10-22  7:11           ` Peter Zijlstra
2020-10-22 10:47             ` Viresh Kumar
2020-10-22 11:45               ` Rafael J. Wysocki
2020-10-22 12:02                 ` default cpufreq gov, was: " Peter Zijlstra
2020-10-22 12:19                   ` Rafael J. Wysocki
2020-10-22 12:29                     ` Peter Zijlstra
2020-10-22 14:52                       ` Mel Gorman
2020-10-22 14:58                         ` Colin Ian King
2020-10-22 15:12                           ` Phil Auld
2020-10-22 16:35                             ` Mel Gorman
2020-10-22 17:59                               ` Rafael J. Wysocki
2020-10-22 20:32                                 ` Mel Gorman
2020-10-22 20:39                                   ` Phil Auld
2020-10-22 15:25                         ` Peter Zijlstra
2020-10-22 15:55                           ` Rafael J. Wysocki
2020-10-22 16:29                           ` Mel Gorman
2020-10-22 20:10                           ` Giovanni Gherdovich
2020-10-22 20:16                             ` Giovanni Gherdovich
2020-10-23  7:03                             ` Peter Zijlstra
2020-10-23 17:46                               ` Tom Lendacky
2020-10-26 19:52                                 ` Fontenot, Nathan
2020-10-22 15:45                       ` A L
2020-10-22 15:55                         ` Vincent Guittot
2020-10-23  5:11                           ` Viresh Kumar
2020-10-22 16:23                   ` [PATCH] cpufreq: Avoid configuring old governors as default with intel_pstate Rafael J. Wysocki
2020-10-23  6:17                     ` Viresh Kumar
2020-10-23 11:59                       ` Rafael J. Wysocki
2020-10-23 15:15                     ` [PATCH v2] " Rafael J. Wysocki
2020-10-27  3:01                       ` Viresh Kumar
2020-10-27 11:11                   ` default cpufreq gov, was: [PATCH] sched/fair: check for idle core Qais Yousef
2020-10-27 11:26                     ` Valentin Schneider
2020-10-27 11:42                       ` Qais Yousef
2020-10-27 11:48                         ` Viresh Kumar [this message]
2020-10-23  6:12                 ` Viresh Kumar
2020-10-23 15:06                   ` Rafael J. Wysocki
2020-10-27  3:01                     ` Viresh Kumar
2020-10-22 11:21             ` AW: " Walter Harms
2020-10-21 12:28     ` Mel Gorman
2020-10-21 12:25   ` Vincent Guittot
2020-10-21 12:47     ` Mel Gorman
2020-10-21 12:56       ` Julia Lawall
2020-10-21 13:18         ` Mel Gorman
2020-10-21 13:24           ` Julia Lawall
2020-10-21 15:08             ` Mel Gorman
2020-10-21 15:18               ` Julia Lawall
2020-10-21 15:23                 ` Vincent Guittot
2020-10-21 15:33                   ` Julia Lawall
2020-10-21 15:19               ` Vincent Guittot
2020-10-21 17:00                 ` Mel Gorman
2020-10-21 17:39                   ` Julia Lawall
2020-10-21 13:48           ` Julia Lawall
2020-10-21 15:26             ` Mel Gorman

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