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From: Vincent Guittot <vincent.guittot@linaro.org>
To: Qais Yousef <qyousef@layalina.io>
Cc: Wyes Karny <wkarny@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	 Ingo Molnar <mingo@kernel.org>,
	linux-kernel@vger.kernel.org,
	 Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	 Juri Lelli <juri.lelli@redhat.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	 Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	 Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>
Subject: Re: [GIT PULL] Scheduler changes for v6.8
Date: Mon, 15 Jan 2024 14:26:21 +0100	[thread overview]
Message-ID: <CAKfTPtAMacH4hKLyttLuQJjzc=D4m864MFaEEwZLG4K8RKTDYA@mail.gmail.com> (raw)
In-Reply-To: <20240115120915.fukpcdumntdsllwi@airbuntu>

On Mon, 15 Jan 2024 at 13:09, Qais Yousef <qyousef@layalina.io> wrote:
>
> On 01/15/24 09:21, Vincent Guittot wrote:
>
> > > Or I've done the math wrong :-) But the two don't behave the same for the same
> > > kernel with and without CPPC.
> >
> > They will never behave the same because they can't
> > - with invariance, the utilization is the utilization at max capacity
> > so we can easily jump several OPP to go directly to the right one
> > - without invariance, the utilization is the utilization at current
> > OPP so we can only jump to a limited number of OPP
>
> I am probably missing some subtlty, but the  behavior looks more sensible to
> me when we divide by current capacity instead of max one.
>
> It seems what you're saying is that the capacity range for each OPP is 0-1024.

Yes that's the case when you don't have frequency invariance

> And that's when we know that we saturated the current capacity level we decide
> to move on.

yes

>
> As I am trying to remove the hardcoded headroom values I am wary of another
> one. But it seems this is bandaid scenario anyway; so maybe I shouldn't worry
> too much about it.
>
>
> Cheers
>
> --
> Qais Yousef

  reply	other threads:[~2024-01-15 13:26 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-28 12:23 [GIT PULL] Scheduler changes for v6.7 Ingo Molnar
2023-10-30 23:50 ` pr-tracker-bot
2024-01-08 14:07 ` [GIT PULL] Scheduler changes for v6.8 Ingo Molnar
2024-01-09  4:04   ` pr-tracker-bot
2024-01-10 22:19   ` Linus Torvalds
2024-01-10 22:41     ` Linus Torvalds
2024-01-10 22:57       ` Linus Torvalds
2024-01-11  8:11         ` Vincent Guittot
2024-01-11 17:45           ` Linus Torvalds
2024-01-11 17:53             ` Linus Torvalds
2024-01-11 18:16               ` Vincent Guittot
2024-01-12 14:23                 ` Dietmar Eggemann
2024-01-12 16:58                   ` Vincent Guittot
2024-01-12 18:18                   ` Qais Yousef
2024-01-12 19:03                     ` Vincent Guittot
2024-01-12 20:30                       ` Linus Torvalds
2024-01-12 20:49                         ` Linus Torvalds
2024-01-12 21:04                           ` Linus Torvalds
2024-01-13  1:04                             ` Qais Yousef
2024-01-13  1:24                               ` Linus Torvalds
2024-01-13  1:31                                 ` Linus Torvalds
2024-01-13 10:47                                   ` Vincent Guittot
2024-01-13 18:33                                     ` Qais Yousef
2024-01-13 18:37                                 ` Qais Yousef
2024-01-11 11:09         ` [GIT PULL] scheduler fixes Ingo Molnar
2024-01-11 13:04           ` Vincent Guittot
2024-01-11 20:48             ` [PATCH] Revert "sched/cpufreq: Rework schedutil governor performance estimation" and dependent commit Ingo Molnar
2024-01-11 22:22               ` Vincent Guittot
2024-01-12 18:24               ` Ingo Molnar
2024-01-12 18:26         ` [GIT PULL] Scheduler changes for v6.8 Ingo Molnar
2024-01-14  9:12         ` Wyes Karny
2024-01-14 11:18           ` Vincent Guittot
2024-01-14 12:37             ` Wyes Karny
2024-01-14 13:02               ` Dietmar Eggemann
2024-01-14 13:05                 ` Vincent Guittot
2024-01-14 13:03               ` Vincent Guittot
2024-01-14 15:12                 ` Qais Yousef
2024-01-14 15:20                   ` Vincent Guittot
2024-01-14 19:58                     ` Qais Yousef
2024-01-14 23:37                       ` Qais Yousef
2024-01-15  6:25                         ` Wyes Karny
2024-01-15 11:59                           ` Qais Yousef
2024-01-15  8:21                       ` Vincent Guittot
2024-01-15 12:09                         ` Qais Yousef
2024-01-15 13:26                           ` Vincent Guittot [this message]
2024-01-15 14:03                             ` Dietmar Eggemann
2024-01-15 15:26                               ` Vincent Guittot
2024-01-15 20:05                                 ` Dietmar Eggemann
2024-01-15  8:42                       ` David Laight
2024-01-14 18:11                 ` Wyes Karny
2024-01-14 18:18                   ` Vincent Guittot
2024-01-11  9:33     ` Ingo Molnar
2024-01-11 11:14     ` [tip: sched/urgent] Revert "sched/cpufreq: Rework schedutil governor performance estimation" and dependent commits tip-bot2 for Ingo Molnar
2024-01-11 20:55     ` [tip: sched/urgent] Revert "sched/cpufreq: Rework schedutil governor performance estimation" and dependent commit tip-bot2 for Ingo Molnar

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