Arch Linux

mgtMobile

Member

Registered: 2022-10-02

Posts: 5

High CPU power usage (in watts) when idle

Hi everyone,
So I've been having this problem on my laptop ever since switching to Arch some months ago.
The CPU power package never goes under 4 watts when idle (power save profile). I've tried every power saving tweak I could find, including switching to other kernels like zen/lts, no luck.
I let it go for a while but recently I've discovered Ubuntu and derivatives doesn't have this problem. Also tried Fedora, Thumbleweed, other Arch derivatives, Artix, no luck.. Actually Ubuntu seems to be the exception in this (Debian?).
CPU power usage in Ubuntu drops to under 1 watt, as it should, as in Windows, better actually... I tested this is Ubuntu 22.04 and 22.10 beta. Kernel version doesn't seem to matter. This works in the live session too.

I really hope someone smarter/more knowledgeable than me sees this thread, I don't want to drop Arch in favor of some Ubuntu based distro, as Arch suits my needs way better, but this problem is really annoying when it comes to battery life and cooling (extra 6-8 degrees hotter in Arch).

The problem seems to be the inability to access higher package C-states, how Ubuntu does it? don't know.. So anyone experienced something similar? Any help/hints/solutions would be greatly appreciated, thanks!

my laptop: Asus S435EA , Intel Tiger Lake Core i5-1135G7, KDE, power-profiles-daemon & thermald
posted this on reddit too..
I also followed the wiki prior and post install.

Last edited by mgtMobile (2022-10-13 12:17:19)

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 15,057

Re: High CPU power usage (in watts) when idle

The only pcm I can find is the aur pacakge at https://aur.archlinux.org/packages/pcm .

Are you using that and if so do you run the same version (202207 ) on those other OSes ?

Do you have other tools to manage power installed / active then the power devil module from kde ?

Welcome to archlinux forums.

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

clean chroot building not flexible enough ?
Try clean chroot manager by graysky

mgtMobile

Member

Registered: 2022-10-02

Posts: 5

Re: High CPU power usage (in watts) when idle

I'm using s-tui and pcm (from aur yes) for benchmarking/monitoring power usage.
I doubt there's inconsistencies between versions/distros, not even using these, just monitoring the cpu temp I can see a 6-8 degree drop in Ubuntu, and sometimes the fan actually stops, something unheard of in Arch. so the issue is real with or without these monitoring tools.
I tried tlp, laptop-mode-tools, auto-cpufreq, I did the powertop tweaks and every other power saving tweak I could find. Nothing works, or they all work the same. The result is I can't see package C-states higher than 2. Somehow in Ubuntu (as in Windows) they go to 7-8 and it automagically does this even running the live media..

LE: oh and I reviewd all the packages Ubuntu uses against my Arch install, they are about the same regarding power management, maybe Ubuntu uses some diffent .conf that I missed, or there's some difference in their kernels? I don't know anymore..

Last edited by mgtMobile (2022-10-02 14:37:46)

xerxes_

Member

Registered: 2018-04-29

Posts: 1,063

Re: High CPU power usage (in watts) when idle

You may compare kernel configs in /proc/config.gz from Ubuntu and Arch (linux or linux-lts): unpack & diff.

mgtMobile

Member

Registered: 2022-10-02

Posts: 5

Re: High CPU power usage (in watts) when idle

I compared the two kernel config files and there are a lot of diffs, almost 600 lines, not all relevant I'm sure.. but I don't really know what they all mean

walkingstickfan

Member

From: USA

Registered: 2021-05-10

Posts: 116

Re: High CPU power usage (in watts) when idle

@mgtMobile: Consider editing your original post and removing the t from High so that others may find your thread if they encounter the same issue.

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Arch Linux with Openbox & Tint2

mgtMobile

Member

Registered: 2022-10-02

Posts: 5

Re: High CPU power usage (in watts) when idle

@walkingstickfan: Did it, thank you for pointing it out!
Unfortunately as far as I know, this issue seems to be related only to my hardware, best advice I got this far is fill out a bug report, which I'm going to..

xerxes_

Member

Registered: 2018-04-29

Posts: 1,063

Re: High CPU power usage (in watts) when idle

Can you post here that kernel config comparison done by diff in code tags?

u666sa

Member

Registered: 2020-08-01

Posts: 70

Re: High CPU power usage (in watts) when idle

Ubuntu is Linux out of the box. Arch is what you make.

https://wiki.archlinux.org/title/CPU_fr … ng_drivers

mgtMobile

Member

Registered: 2022-10-02

Posts: 5

Re: High CPU power usage (in watts) when idle

Sorry for the delay, busy week, but I found a fix!
Disabling VMD/RST in Bios solved this!
Apparently there is a bug in the VMD Linux driver, however Ubuntu kernels don't seem to suffer from this.
I will post a kernel config comparison maybe the cause will be apparent.