Daemon to set scaling_max_freq according to CPU temperature

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

Hi All.

I recently got myself a new PC based on a Asrock J5040-ITX mainboard. The processor is 2.0GHz but thanks to a turbo mode it can scale from 800MHz upto 3.2GHz.

When using a standard cpufreq governor it will be set to 3.2GHz when under load and it will stay there. Since this is a fanless system, heat builds up and eventually even reaches it's critical temperature (95 degrees Celsius).
One way to prevent that from happening is to lower the scaling_max_freq cpufreq setting, but of course if temperatures allow it i'd like to use the full capability of the CPU. So what i need is a daemon that monitors the CPU temperature and lowers the scaling_max_freq when the temperature rises above a certain threshold and increases scaling_max_freq if the temperature allows it.

I made a small proof-of-concept shell script that does exactly that and it works. Now I expect this problem to be so common that i expect someone else has made a nice program that does this, i've checked all programs in sys-power/ but I can't find it. Is anyone aware of a program that does this?

Thanks in advance.
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pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

As it seems my case is not as common as i expected, and i haven't been able to find a program that does what i need. So i decided to write something myself, the code including an ebuild is available here: https://code.pa4wdh.nl.eu.org/tools/cputemp2maxfreq/about/

I hope it helps someone else too

. Feedback is welcome of course.
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USE="-war" emerge --newuse @world

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Zucca · Posted: Sun Jul 21, 2024 10:14 am Post subject:

Any plans to submit an ebuild to ::guru? ;)
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pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

So far I don't have any plans to do that.
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The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

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Zucca · Posted: Sun Jul 21, 2024 11:59 am Post subject:

So maybe I'll create one for my overlay. ;)

EDIT: You seem to have a gentoo/ directory on the git repository, which contains ebuilds for it, like https://code.pa4wdh.nl.eu.org/tools/cputemp2maxfreq/plain/gentoo/cputemp2maxfreq-0.3.ebuild

Do you have a dedicated overlay for these?
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pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

I indeed made an ebuild, it's what i use to install it on my own PC

For personal use i simply add the ebulid to an existing local overlay, I don't have any other (published) overlay dedicated to this. Feel free to add it to your own overlay.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

Zucca · Posted: Sun Jul 21, 2024 5:42 pm Post subject:

Zucca · Posted: Sun Jul 21, 2024 11:02 pm Post subject:

Done.
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NichtDerHans · Apprentice Joined: 27 Jan 2023 Posts: 173

Could you give an example of a start command with parameters? Iam not sure if I do it right.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

On my system it's running with these parameters:

Zucca · Posted: Wed Jul 24, 2024 9:04 am Post subject:

Hm. Looks like my system reports CPU temperature on a another location: /sys/class/hwmon/hwmon4/temp1_input. That's not a problem, but the value got from there is in millicelcius. So I tried to set the upper temperature limit as millicelcius... Nope.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

As far as i'm aware all temperatures in sysfs are reported in millicelsius, the -t parameter given to my daemon gets multiplied by 1000 to facilitate this so you should be fine by just pointing -i to the right location.

And thanks for pointing out the typo

_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

Zucca · Posted: Wed Jul 24, 2024 9:58 am Post subject:

Ah. My problems were because of a silly typo.
Because the daemon failed to start at first, I then ran its init script with --debug, and copied the command line...

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

Good you found that. I'm interested to hear how it works for you.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NichtDerHans · Apprentice Joined: 27 Jan 2023 Posts: 173

Intel i7-1165G7

There is no governor conservative. So I start with:

logrusx · Advocate Joined: 22 Feb 2018 Posts: 2149

logrusx · Advocate Joined: 22 Feb 2018 Posts: 2149

@pa4wdh, can you explain this:

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

@NichtDerHans:
The performance governor should also work. The conservative governor makes the effect bigger because it scales the CPU frequency down then the load is low, allowing your CPU to cool down faster.

Your transition delay (read from /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency) is reported as 0 which is odd. It should be the delay between setting a frequency and it physically being done in the CPU. As a safety measure the daemon sets the new frequency, waits for the transition delay, reads the frequency again, and expects the readout to be the frequency it set. For example on my system this delay is 20000 (20ms).
Since in your case the delay is reported to be 0, the check is done immediately which most likely is too short for anything to happen.

I could make a new parameter so you can supply your own value for the delay.

@logrusx:
That log odd indeed. The if statements use higher/lower than, so they shouldn't trigger when current value==new value. Are you using any special CFLAGS?
Maybe running with debug info gives more insight in what's happening. That would require manual compiling (not via portage) and changing DEBUG_ALL to 3 in debug.h. Is that something you can do?
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

logrusx · Advocate Joined: 22 Feb 2018 Posts: 2149

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

Your reply was faster than my edit on my message, so to be sure i'm repeating my edit here:
Maybe running with debug info gives more insight in what's happening. That would require manual compiling (not via portage) and changing DEBUG_ALL to 3 in debug.h. Is that something you can do?
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

logrusx · Advocate Joined: 22 Feb 2018 Posts: 2149

logrusx · Advocate Joined: 22 Feb 2018 Posts: 2149

//link to crappy file sharing service removed

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 867

I've made a new (0.4) version of the daemon which includes a parameter to manually set the transition delay.
@NichtDerHans: This should help with you setup. Valid values are 0...100000, 50000 should be a safe first try. When it's too low you'll see it exit immediately (just like it did now), and increase by 10000 until it works.

@logrusx:
Thanks for your effort to collect the logs. Unfortunately the website you link to redirects me to very shady websites which i don't like to visit. Could you share your log via a different service? (or simply post the relevant part of it here?)
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

logrusx · Advocate Joined: 22 Feb 2018 Posts: 2149

Zucca · Posted: Fri Jul 26, 2024 8:40 am Post subject:

I've found out that most of the time, when submitting long logs, one can pipe the log trough a compressor and some base[N] encoder, so that the log file size does not exceed the pastebin size limit.