linux-kernel - RE: [PATCH v2 0/2] cpufreq: Specify the default governor on command line

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Date:   Tue, 23 Jun 2020 17:07:52 -0700
From:   "Doug Smythies" <dsmythies@...us.net>
To:     "'Quentin Perret'" <qperret@...gle.com>
Cc:     <arnd@...db.de>, <mpe@...erman.id.au>, <benh@...nel.crashing.org>,
        <paulus@...ba.org>, <mingo@...hat.com>, <peterz@...radead.org>,
        <juri.lelli@...hat.com>, <vincent.guittot@...aro.org>,
        <linuxppc-dev@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
        <linux-pm@...r.kernel.org>, <kernel-team@...roid.com>,
        <tkjos@...gle.com>, <adharmap@...eaurora.org>,
        <viresh.kumar@...aro.org>, <rafael@...nel.org>, <rjw@...ysocki.net>
Subject: RE: [PATCH v2 0/2] cpufreq: Specify the default governor on command line

Hi Quentin,
Thanks for your quick reply.

On 2020.06.23 11:05 Quentin Perret wrote: 

> Hi Doug,
> 
> On Tuesday 23 Jun 2020 at 10:54:33 (-0700), Doug Smythies wrote:
> > Hi Quentin,
> >
> > Because I am lazy and sometimes do not want to recompile
> > the distro source, I have a need/desire for this.
> 
> Good to know I'm not the only one ;-)
> 
> > Tested these two grub command lines:
> >
> > GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 consoleblank=300 intel_pstate=disable
> cpufreq.default_governor=schedutil cpuidle_sysfs_switch cpuidle.governor=teo"
> >
> > And
> >
> > #GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 consoleblank=450 intel_pstate=passive
> cpufreq.default_governor=schedutil cpuidle_sysfs_switch cpuidle.governor=teo"
> >
> > And all worked as expected. I use Ubuntu as my distro, and also had to disable a startup script that
> switches to "ondemand", or similar, after 1 minute.
> 
> Good, thanks for giving it a try.
> 
> > As a side note (separate subject, but is one reason I tried it):
> > My i5-9600K based computer seems to hit a power limit during boot approximately 3 seconds after
> kernel selection on grub.
> > This had no effect on that issue (even when selecting powersave governor).
> 
> Interesting ... Could you confirm that compiling with powersave as
> default doesn't fix the issue either?

No, it doesn't (good idea for a test though).
However, the big mains spike is also gone. So, I no longer know why those power
limit log bits are always set after boot.

> 
> Other question, when does the intel_pstate driver start on your device?
> Before or after that 3 seconds boot time?

Before, if I understand correctly (from dmesg):

[    0.468969] intel_pstate: Intel P-state driver initializing

I'll attach a couple of annotated mains power graphs.
(which will likely get stripped from the on-list version of this e-mail).

Currently, I am drowning in stuff that doesn't work, and will put
this aside for now. I'll revive this as a new thread or a bugzilla
eventually.

I also tried booting with turbo disabled, no difference.

Thanks for this patch set.

... Doug


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Download attachment "reboot-mains-power4.png" of type "image/png" (34687 bytes)