On 2020.06.23 07:22 Quentin Perret wrote:

This series enables users of prebuilt kernels (e.g. distro kernels) to
specify their CPUfreq governor of choice using the kernel command line,
instead of having to wait for the system to fully boot to userspace to
switch using the sysfs interface. This is helpful for 2 reasons:
  1. users get to choose the governor that runs during the actual boot;
  2. it simplifies the userspace boot procedure a bit (one less thing to
     worry about).

To enable this, the first patch moves all governor init calls to
core_initcall, to make sure they are registered by the time the drivers
probe. This should be relatively low impact as registering a governor
is a simple procedure (it gets added to a llist), and all governors
already load at core_initcall anyway when they're set as the default
in Kconfig. This also allows to clean-up the governors' init/exit code,
and reduces boilerplate.

The second patch introduces the new command line parameter, inspired by
its cpuidle counterpart. More details can be found in the respective
patch headers.

Changes in v2:
 - added Viresh's ack to patch 01
 - moved the assignment of 'default_governor' in patch 02 to the governor
   registration path instead of the driver registration (Viresh)

Thanks,
Quentin

Quentin Perret (2):
  cpufreq: Register governors at core_initcall
  cpufreq: Specify default governor on command line

 .../admin-guide/kernel-parameters.txt         |  5 ++++
 Documentation/admin-guide/pm/cpufreq.rst      |  6 ++---
 .../platforms/cell/cpufreq_spudemand.c        | 26 ++-----------------
 drivers/cpufreq/cpufreq.c                     | 23 ++++++++++++----
 drivers/cpufreq/cpufreq_conservative.c        | 22 ++++------------
 drivers/cpufreq/cpufreq_ondemand.c            | 24 +++++------------
 drivers/cpufreq/cpufreq_performance.c         | 14 ++--------
 drivers/cpufreq/cpufreq_powersave.c           | 18 +++----------
 drivers/cpufreq/cpufreq_userspace.c           | 18 +++----------
 include/linux/cpufreq.h                       | 14 ++++++++++
 kernel/sched/cpufreq_schedutil.c              |  6 +----
 11 files changed, 62 insertions(+), 114 deletions(-)

--
2.27.0.111.gc72c7da667-goog

Hi Quentin,

Because I am lazy and sometimes do not want to recompile
the distro source, I have a need/desire for this.

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.

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).

... Doug