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From: Steve Muckle <steve.muckle@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Juri Lelli <juri.lelli@arm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Linux PM list <linux-pm@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v10 1/3] cpufreq: Add mechanism for registering utilization update callbacks
Date: Mon, 22 Feb 2016 19:58:47 -0800	[thread overview]
Message-ID: <56CBD8F7.3090502@linaro.org> (raw)
In-Reply-To: <1797575.PjqbkdCLyN@vostro.rjw.lan>

On 02/19/2016 02:35 PM, Rafael J. Wysocki wrote:
>> The scheduler hooks for utilization-based cpufreq operation deserve a
>> lot more debate I think. They could quite possibly have different
>> requirements than hooks which are chosen just to guarantee periodic
>> callbacks into sampling-based governors.
> 
> Yes, they could.
> 
> The point here, though, is that even the sampling-based governors may 
> benefit from using the numbers provided by the scheduler instead of trying
> to come up with analogous numbers themselves.

It seems premature to me to merge supporting infrastructure (the
utilization hooks) before we have changes, be it modifications to the
sampling based governors to use utilization or a scheduler-guided
governor, which are well tested and proven to yield reasonable
performance and power across various platforms and workloads.

Perhaps I'm a pessimist but I think it's going to be a challenge to get
utilization-based cpufreq on par, and I think getting the hooks right
will be part of that challenge.

>> For my part I think it would be best if the util/max parameters are
>> omitted
> 
> OK, so please see the patch I've just sent to Juri:
> 
> https://patchwork.kernel.org/patch/8364621/

Looked good to me.

thanks,
Steve

  reply	other threads:[~2016-02-23  3:58 UTC|newest]

Thread overview: 134+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-29 22:52 [PATCH 0/3] cpufreq: Replace timers with utilization update callbacks Rafael J. Wysocki
2016-01-29 22:53 ` [PATCH 1/3] cpufreq: Add a mechanism for registering " Rafael J. Wysocki
2016-02-04  3:31   ` Viresh Kumar
2016-01-29 22:56 ` [PATCH 2/3] cpufreq: intel_pstate: Replace timers with " Rafael J. Wysocki
2016-01-29 22:59 ` [PATCH 3/3] cpufreq: governor: " Rafael J. Wysocki
2016-02-03  1:16   ` [Update][PATCH " Rafael J. Wysocki
2016-02-04  4:49     ` Viresh Kumar
2016-02-04 10:54       ` Rafael J. Wysocki
2016-02-05  1:28     ` [PATCH 3/3 v3] " Rafael J. Wysocki
2016-02-05  6:50       ` Viresh Kumar
2016-02-05 13:36         ` Rafael J. Wysocki
2016-02-05 14:47           ` Viresh Kumar
2016-02-05 23:10             ` Rafael J. Wysocki
2016-02-07  9:10               ` Viresh Kumar
2016-02-07 14:43                 ` Rafael J. Wysocki
2016-02-08  2:08                   ` Rafael J. Wysocki
2016-02-08 11:52                     ` Viresh Kumar
2016-02-08 12:52                       ` Rafael J. Wysocki
2016-02-08 13:40                         ` Rafael J. Wysocki
2016-02-05 23:01           ` Rafael J. Wysocki
2016-02-06  3:40       ` [PATCH 3/3 v4] " Rafael J. Wysocki
2016-02-07  9:20         ` Viresh Kumar
2016-02-07 14:36           ` Rafael J. Wysocki
2016-02-07 14:50         ` [PATCH 3/3 v5] " Rafael J. Wysocki
2016-02-07 15:36           ` Viresh Kumar
2016-02-09 10:01           ` Gautham R Shenoy
2016-02-09 18:49             ` Rafael J. Wysocki
2016-02-03 22:20 ` [PATCH 0/3] cpufreq: " Rafael J. Wysocki
2016-02-04  0:08   ` Srinivas Pandruvada
2016-02-04 17:16     ` Rafael J. Wysocki
2016-02-04 10:51   ` Juri Lelli
2016-02-04 17:19     ` Rafael J. Wysocki
2016-02-08 23:06   ` Rafael J. Wysocki
2016-02-09  0:39     ` Steve Muckle
2016-02-09  1:01       ` Rafael J. Wysocki
2016-02-09 20:05         ` Rafael J. Wysocki
2016-02-10  1:02           ` Steve Muckle
2016-02-10  1:57             ` Rafael J. Wysocki
2016-02-10  3:09               ` Rafael J. Wysocki
2016-02-10 19:47                 ` Steve Muckle
2016-02-10 21:49                   ` Rafael J. Wysocki
2016-02-10 22:07                     ` Steve Muckle
2016-02-10 22:12                       ` Rafael J. Wysocki
2016-02-11 11:59             ` Peter Zijlstra
2016-02-11 12:24               ` Juri Lelli
2016-02-11 15:26                 ` Peter Zijlstra
2016-02-11 18:23                   ` Vincent Guittot
2016-02-12 14:04                     ` Peter Zijlstra
2016-02-12 14:48                       ` Vincent Guittot
2016-03-01 13:58                         ` Peter Zijlstra
2016-03-01 14:17                           ` Juri Lelli
2016-03-01 14:24                             ` Peter Zijlstra
2016-03-01 14:26                               ` Peter Zijlstra
2016-03-01 14:42                                 ` Juri Lelli
2016-03-01 15:04                                   ` Peter Zijlstra
2016-03-01 19:49                                     ` Rafael J. Wysocki
2016-03-01 14:58                           ` Vincent Guittot
2016-02-11 17:06               ` Steve Muckle
2016-02-11 17:30                 ` Peter Zijlstra
2016-02-11 17:34                   ` Rafael J. Wysocki
2016-02-11 17:38                     ` Peter Zijlstra
2016-02-11 18:52                   ` Steve Muckle
2016-02-11 19:04                     ` Rafael J. Wysocki
2016-02-12 13:43                       ` Rafael J. Wysocki
2016-02-12 14:10                     ` Peter Zijlstra
2016-02-12 16:01                       ` Rafael J. Wysocki
2016-02-12 16:15                         ` Rafael J. Wysocki
2016-02-12 16:53                           ` Ashwin Chaugule
2016-02-12 23:14                             ` Rafael J. Wysocki
2016-02-12 17:02                         ` Doug Smythies
2016-02-12 23:17                           ` Rafael J. Wysocki
2016-02-10 12:33           ` Juri Lelli
2016-02-10 13:23             ` Rafael J. Wysocki
2016-02-10 14:03               ` Juri Lelli
2016-02-10 14:26                 ` Rafael J. Wysocki
2016-02-10 14:46                   ` Juri Lelli
2016-02-10 15:46                     ` Rafael J. Wysocki
2016-02-10 16:05                       ` Juri Lelli
2016-02-11 11:51           ` Peter Zijlstra
2016-02-11 12:08             ` Rafael J. Wysocki
2016-02-11 15:29               ` Peter Zijlstra
2016-02-11 15:58                 ` Rafael J. Wysocki
2016-02-11 20:47               ` Rafael J. Wysocki
2016-02-10 15:17 ` [PATCH v6 " Rafael J. Wysocki
2016-02-10 15:21   ` [PATCH v6 1/3] cpufreq: Add mechanism for registering " Rafael J. Wysocki
2016-02-10 23:01     ` [PATCH v7 " Rafael J. Wysocki
2016-02-11 17:30       ` [PATCH v8 " Rafael J. Wysocki
2016-02-12 13:16         ` [PATCH v9 " Rafael J. Wysocki
2016-02-15 21:47           ` [PATCH v10 " Rafael J. Wysocki
2016-02-18 20:22             ` Rafael J. Wysocki
2016-02-19  8:09               ` Juri Lelli
2016-02-19 16:42                 ` Srinivas Pandruvada
2016-02-19 17:26                   ` Juri Lelli
2016-02-19 22:26                     ` Rafael J. Wysocki
2016-02-22  9:42                       ` Juri Lelli
2016-02-22 21:41                         ` Rafael J. Wysocki
2016-02-23 11:10                           ` Juri Lelli
2016-02-24  1:52                             ` Rafael J. Wysocki
2016-02-22 10:45                       ` Viresh Kumar
2016-02-19 17:28                   ` Steve Muckle
2016-02-19 22:35                     ` Rafael J. Wysocki
2016-02-23  3:58                       ` Steve Muckle [this message]
2016-02-22 10:52                     ` Peter Zijlstra
2016-02-22 14:33                       ` Vincent Guittot
2016-02-22 15:31                         ` Peter Zijlstra
2016-02-22 14:40                       ` Juri Lelli
2016-02-22 15:42                         ` Peter Zijlstra
2016-02-22 21:46                       ` Rafael J. Wysocki
2016-02-19 22:14                 ` Rafael J. Wysocki
2016-02-22  9:32                   ` Juri Lelli
2016-02-22 21:26                     ` Rafael J. Wysocki
2016-02-23 11:01                       ` Juri Lelli
2016-02-24  2:01                         ` Rafael J. Wysocki
2016-03-08 19:24                           ` Michael Turquette
2016-03-08 20:40                             ` Rafael J. Wysocki
     [not found]                               ` <20160308220632.4103.13377@quark.deferred.io>
2016-03-08 22:43                                 ` Rafael J. Wysocki
2016-03-09 12:35             ` Peter Zijlstra
2016-03-09 13:22               ` Rafael J. Wysocki
2016-03-09 13:32               ` Ingo Molnar
2016-03-09 13:39                 ` Rafael J. Wysocki
2016-03-10  2:12               ` Vincent Guittot
2016-02-10 15:25   ` [PATCH v6 2/3] cpufreq: intel_pstate: Replace timers with " Rafael J. Wysocki
2016-02-10 15:36   ` [PATCH v6 3/3] cpufreq: governor: " Rafael J. Wysocki
2016-02-10 23:11   ` [PATCH v6 0/3] cpufreq: " Doug Smythies
2016-02-10 23:17     ` Rafael J. Wysocki
2016-02-11 22:50       ` Doug Smythies
2016-02-11 23:28         ` Rafael J. Wysocki
2016-02-12  1:02           ` Doug Smythies
2016-02-12  1:20             ` Rafael J. Wysocki
2016-02-12  7:25         ` Doug Smythies
2016-02-12 13:39           ` Rafael J. Wysocki
2016-02-12 17:33             ` Doug Smythies
2016-02-12 23:21               ` Rafael J. Wysocki
2016-02-11  6:02     ` Srinivas Pandruvada

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