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cpufrequtils on a Pogo v4

Posted by dhargens 
cpufrequtils on a Pogo v4
March 01, 2024 10:29PM
I just learned about 'cpufrequtils' from a discussion here, and having installed it on a Kace M300 and have it work as expected, I also set it up on a Pogo v4 - but it doesn't throttle down, it's always at 800MHz. Rebooting didn't affect it (didn't expect it to, but always try all things).

Here's the outputs on the Pogo v4:
# cpufreq-info -p
200000 800000 ondemand
# cpufreq-info
analyzing CPU 0:
  driver: kirkwood-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 5.0 us.
  hardware limits: 200 MHz - 800 MHz
  available frequency steps: 800 MHz, 200 MHz
  available cpufreq governors: powersave, ondemand, userspace, conservative, performance
  current policy: frequency should be within 200 MHz and 800 MHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 800 MHz.

AFAICT, it's set to 'ondemand', which should throttle. Given how hot these things run all the time, I thought it'd be a good idea to slow it down until needed. So, I'm confused why it's not throttling as expected.
Debian 12.4    6.6.3-kirkwood-tld-1
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 01, 2024 11:06PM
While digging around for answers, I also found the package 'linux-cpupower', which seems to have replaced cpufrequtils. According to https://wiki.debian.org/CpuFrequencyScaling:
cpufreq is being replaced by cpupower.
...and https://packages.debian.org/bookworm/linux-cpupower:
The cpupower command allows inspection and control of cpufreq and cpuidle tunables for
hardware that supports these features. It replaces "cpufreq-info" and "cpufreq-set" in cpufrequtils.
Installing it only required 2 dependencies, not the bunch that cpufrequtils does, and it looks the same to me when run.

I'm running it for a while and see how it goes.



Edited 1 time(s). Last edit at 03/01/2024 11:39PM by dhargens.
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 01, 2024 11:38PM
Update: installing linux-cpupower didn't seem to make a difference in CPU frequency - it constantly sits at 800MHz. It could be that this little thing is taxed already so it'll never throttle down, but I have no way of knowing that or confirming it.
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 02, 2024 08:39PM
dhargens,

It must be that something is running in the system, and cpufrequtils decided to raise it to 800 Mhz. I've recalled it works on this Pogo V4.

Try this to prove that there is no problem particular to the Pogo V4.
cpufreq-set -g powersave
And then
cpufreq-info
That should bring it down to 200 MHz.

-bodhi
===========================
Forum Wiki
bodhi's corner (buy bodhi a beer)
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 08, 2024 06:54PM
Sorry for the delay in responding.

Yes, it does stay at 200 when set to 'powersave'. I'm using linux-cpupower instead of cpufrequtils, but it works the same.
# cpupower frequency-set -g powersave
# cpupower frequency-info
analyzing CPU 0:
  driver: kirkwood-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 5.0 us
  hardware limits: 200 MHz - 800 MHz
  available frequency steps:  800 MHz, 200 MHz
  available cpufreq governors: powersave ondemand userspace conservative performance
  current policy: frequency should be within 200 MHz and 800 MHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 200 MHz (asserted by call to kernel)
It sticks there as expected while doing work and idling.
I'd kinda like it to idle until it's needed, but it's ok the way it is. Besides, I didn't know about it before and everything was fine, so I'll go with that.
It's weird that basically nothing's running on this box but it's pegging the cpu to 800MHz.
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 08, 2024 07:15PM
> I'd kinda like it to idle until it's needed, but
> it's ok the way it is. Besides, I didn't know
> about it before and everything was fine, so I'll
> go with that.
> It's weird that basically nothing's running on
> this box but it's pegging the cpu to 800MHz.

I'm not sure why this box either. On other Kirkwood boxes, ondemand governor would bring it down to a lowest frequency when idle. So it is not cpufreq itself, which does what it suppose to do.

However, I'd not worry much about the power saving. I don't think the lower CPU frequency will save that much electricity anyway. If any gain to be had, I think it's the thermal, which is more significant since it will run cooler.

-bodhi
===========================
Forum Wiki
bodhi's corner (buy bodhi a beer)
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 08, 2024 07:26PM
bodhi Wrote:
-------------------------------------------------------
> However, I'd not worry much about the power
> saving. I don't think the lower CPU frequency will
> save that much electricity anyway. If any gain to
> be had, I think it's the thermal, which is more
> significant since it will run cooler.

I'd agree - thermal reduction is what I was hoping for, since it's a toasty little puck!
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 08, 2024 08:18PM
> I'd agree - thermal reduction is what I was hoping
> for, since it's a toasty little puck!

These plugs should always have silicon/felt feet! buy a few at your local HW store or Waltmart (if you are in US). Raise it about >= 1/4 inch high.

Example:
https://www.amazon.com/Black-Self-Adhesive-Felt-Bumpers/dp/B07DYQJRDB

-bodhi
===========================
Forum Wiki
bodhi's corner (buy bodhi a beer)



Edited 1 time(s). Last edit at 03/08/2024 08:37PM by bodhi.
Re: cpufrequtils / linux-cpupower on a Pogo v4
March 08, 2024 10:39PM
I have the original feet on it too! The top USB drive is quite hot in operation, and even when a drive is on the back ports it's warm too. I'd hoped a slower speed would help it.
No worries though. It works.
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