Undervolting CPU with ubuntu 16.04

Question

I was looking into undervolting my laptop CPU. I could only find guides on phc that are said to be outdated. Is there a tool for that in the new version? Is it possible with TLP?

So far this looks the best information out there: https://github.com/tiziw/iuvolt — Postadelmaga, Mar 08 '18 at 16:20
even better is this: https://github.com/georgewhewell/undervolt — PawełG, Jun 05 '18 at 05:47

score 1 · Answer 1 · edited Apr 13 '17 at 12:25

1

Yes, with TLP you can scale you CPU frequency (Look at this post: TLP don't change CPU frequency). You can specify to reduce the CPU frequency.

CPU_SCALING_GOVERNOR_ON_AC=powersave
CPU_SCALING_GOVERNOR_ON_BAT=powersave

More info here: http://linrunner.de/en/tlp/docs/tlp-configuration.html

However I found another article about CPU limiting

http://blog.scoutapp.com/articles/2014/11/04/restricting-process-cpu-usage-using-nice-cpulimit-and-cgroups

Although, it isn't about limit CPU frequency, you could reduce your CPU load/consumption with an application like cpulimit (https://github.com/opsengine/cpulimit)

Hope this helps.

edited Apr 13 '17 at 12:25

Community

1

answered Jun 28 '16 at 16:30

FabricioFCarv

170

2

Thanks, but I was not interested in decreasing frequency. This could be done with for file in /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq; do echo "3500000" > $file; done I was specifically interested in decreasing voltage per frequency. – amanusk Jun 28 '16 at 21:24
I misunderstood, sorry. But TLP can control undervolting ability, but I couldn't find and tool to do it. However I found a good tutorial: http://www.ullright.org/ullWiki/show/ubuntu-undervoltage-linux-ppc – FabricioFCarv Jun 30 '16 at 13:04

score 0 · Answer 2 · answered Apr 09 '17 at 03:00

0

You need a PHC module to start undevolting, see this forum: http://www.linux-phc.org/forum/index.php.

However, this is not compatible with newer intel processors that use intel p-states, instead of the old acpi-cpufreq (google " Undervolting Ivy bridge core i7 laptop with Ubuntu 16.04 - TLP & PHC not suitable"). It appears that we might never be able to undervolt in newer PCs using linux unless somebody with coding experience steps up to the task....

Unless you are using an older laptop, then you should find your answer in the first link ;) and a compatible PHC module here: http://www.linux-phc.org/forum/viewtopic.php?f=7&t=267. The tutorial suggested by FabricioFCarv should be fine (have not tested myself).

Good luck!

answered Apr 09 '17 at 03:00

BNDR

33

1

Do you have any suggestions for AMD CPUs/GPUs? – Csaba Toth Mar 07 '18 at 01:27
Sorry, I am not an expert so I cannot draw recommendations. But I bet that there is someone out there with your same questions, the task is finding them! – BNDR Mar 21 '18 at 15:52
@CsabaToth turionpowercontrol works – Suici Doga May 02 '18 at 03:33
Seems like there is a solution for newer intel processors here – forgetso Apr 15 '19 at 20:21

Undervolting CPU with ubuntu 16.04

2 Answers2