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From: Peter Zijlstra <peterz@infradead.org>
To: Doug Smythies <dsmythies@telus.net>
Cc: "'Rafael J. Wysocki'" <rafael@kernel.org>,
	'Giovanni Gherdovich' <ggherdovich@suse.com>,
	"'Rafael J. Wysocki'" <rjw@rjwysocki.net>,
	'Linux PM' <linux-pm@vger.kernel.org>,
	'LKML' <linux-kernel@vger.kernel.org>,
	'Viresh Kumar' <viresh.kumar@linaro.org>,
	'Srinivas Pandruvada' <srinivas.pandruvada@linux.intel.com>,
	efault@gmx.de, Mel Gorman <mgorman@suse.de>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Juri Lelli <juri.lelli@gmail.com>
Subject: Re: [PATCH v1 0/4] cpufreq: Allow drivers to receive more information from the governor
Date: Fri, 18 Dec 2020 16:32:31 +0100	[thread overview]
Message-ID: <20201218153231.GB2414@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <001d01d6cd96$601c8a80$20559f80$@net>

On Tue, Dec 08, 2020 at 11:14:36AM -0800, Doug Smythies wrote:
> At least on my system, it is most evident for some of the pipe type tests,
> where the schedutil governor has never really known what to do. This patch
> set seems to add enough of a downward bias that this version of the schedutil
> governor now behaves much like the other versions

Yeah, pipe relies on task-task interaction, where one task waits on
another, and by boosting the producer the consumer can start earlier and
we get more cycles done etc.. Rather similar to IO-wait, where by
boosting the producer we gain throughput.

schedutil doesn't track anything useful here, but it is a semi common
pattern and it would be really good if we could somehow fix this.

We obviously have access to the task A wakes task B information, but I'm
not sure what to do with it, we're tried some things like this in the
past (although for slightly different reasons) and they've always ended
up being a mess :/

  parent reply	other threads:[~2020-12-18 15:33 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-07 16:25 Rafael J. Wysocki
2020-12-07 16:28 ` [PATCH v1 1/4] cpufreq: schedutil: Add util to struct sg_cpu Rafael J. Wysocki
2020-12-08  8:33   ` Viresh Kumar
2020-12-09 17:17     ` Rafael J. Wysocki
2020-12-07 16:29 ` [PATCH v1 2/4] cpufreq: schedutil: Adjust utilization instead of frequency Rafael J. Wysocki
2020-12-08  8:51   ` Viresh Kumar
2020-12-08 17:01     ` Rafael J. Wysocki
2020-12-09  5:16       ` Viresh Kumar
2020-12-09 15:32         ` Rafael J. Wysocki
2020-12-14 11:07           ` Viresh Kumar
2020-12-07 16:35 ` [PATCH v1 3/4] cpufreq: Add special-purpose fast-switching callback for drivers Rafael J. Wysocki
2020-12-08  9:02   ` Viresh Kumar
2020-12-15  4:16     ` Viresh Kumar
2020-12-15 15:38       ` Rafael J. Wysocki
2020-12-07 16:38 ` [PATCH v1 4/4] cpufreq: intel_pstate: Implement the ->adjust_perf() callback Rafael J. Wysocki
2020-12-08 12:43   ` Peter Zijlstra
2020-12-08 17:10     ` Rafael J. Wysocki
2020-12-08 16:30 ` [PATCH v1 0/4] cpufreq: Allow drivers to receive more information from the governor Giovanni Gherdovich
2020-12-08 17:13   ` Rafael J. Wysocki
2020-12-08 19:14     ` Doug Smythies
2020-12-13 19:12       ` Doug Smythies
2020-12-18 15:32       ` Peter Zijlstra [this message]
2020-12-14 20:01 ` [PATCH v2 0/3] " Rafael J. Wysocki
2020-12-14 20:04   ` [PATCH v2 1/3] cpufreq: schedutil: Add util to struct sg_cpu Rafael J. Wysocki
2020-12-14 20:08   ` [PATCH v2 2/3] cpufreq: Add special-purpose fast-switching callback for drivers Rafael J. Wysocki
2020-12-14 20:09   ` [PATCH v2 3/3] cpufreq: intel_pstate: Implement the ->adjust_perf() callback Rafael J. Wysocki
2020-12-15  3:29     ` Srinivas Pandruvada
2020-12-15  4:16   ` [PATCH v2 0/3] cpufreq: Allow drivers to receive more information from the governor Viresh Kumar
2020-12-17 15:26   ` Doug Smythies
2020-12-21 10:41     ` Rafael J. Wysocki
2020-12-18 16:11   ` Giovanni Gherdovich
2020-12-21 16:11     ` Rafael J. Wysocki
2020-12-23 13:06       ` Giovanni Gherdovich
2020-12-28 19:11         ` Rafael J. Wysocki

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