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#1 2022-03-28 20:49:37

westlaw
Member
Registered: 2022-03-28
Posts: 4

ThinkPad X270 CPU Scaling issues

Hi,
My ThinkPad X270 exhibits some weird behaviour.
I'm running Arch Linux and GNOME.
The CPU is a i7-6600U.

While plugged into the wall, everything works as expected, the CPU scales it's frequency up and down.

But when unplugging the power cord, the CPU is stuck at 400MHz which makes even an optimized Linux system unusable...

I tried manually setting the frequency and changing the governor using cpupower but it didn't help.

Thermald is also not installed.

Any ideas on what could be the culprit?

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#2 2022-03-29 00:44:54

PutridPete
Member
Registered: 2021-10-25
Posts: 13

Re: ThinkPad X270 CPU Scaling issues

Recently I rescued a Thinkpad 11e by installing Debian to it. I was facing a similar issue, and what fixed it for me was going into the BIOS/UEFI, then into a section called 'config' and later 'power', and adjust the settings there to 'maximum performance' for when on battery. Obviously this will consume more of your charge, but the computer will become faster and responsive. Since you have a different model, I'm not sure if the same or similar settings are present for your machine, so give it a check and try to find something like it. Perhaps it can help. I also got rid of a setting called "OS Optimized defaults" and that helped with performance too.

Last edited by PutridPete (2022-03-29 00:46:33)

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#3 2022-03-29 06:53:08

westlaw
Member
Registered: 2022-03-28
Posts: 4

Re: ThinkPad X270 CPU Scaling issues

Hi, I already tried that.
The settings already all are at maximum performance.
OS optimized defaults are off.

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#4 2022-03-29 15:04:09

PutridPete
Member
Registered: 2021-10-25
Posts: 13

Re: ThinkPad X270 CPU Scaling issues

Have you tried taking a look at EPB? It manages performance for intel CPUs under a different layer than what frequency scaling provides. It could be that once the laptop is unplugged, EPB is set to highest energy saving.

If you're already using cpupower, you can try the command:

sudo cpupower set -b 6

This will set the profile to normal. You can also try 0 for maximum performance.

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#5 2022-03-29 15:11:33

westlaw
Member
Registered: 2022-03-28
Posts: 4

Re: ThinkPad X270 CPU Scaling issues

I set it to the value. Let's see if that helps.
Sometimes it just works, but then after suspend or sleep it would again be stuck at 400 MHz.

Will this setting persist after reboots?

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#6 2022-03-29 15:58:04

PutridPete
Member
Registered: 2021-10-25
Posts: 13

Re: ThinkPad X270 CPU Scaling issues

It does for me. After a reboot, you can display the EPB value for all cores with the command:

sudo cpupower -c all info -b

If you're having performance issues after suspend/hibernate, my experience is that it often happens on my thinkpad when I keep a browser opened before going into either mode. If you've mistakenly done so with a browser open, I believe a relog of your user can help, if not then a reboot.

I'm sure there's a better solution out there, but I haven't bothered to troubleshoot it properly since personally, I rarely use suspend/hibernate. Much rather turn on or off my laptop as I see fit. I remove suspend from when I close my lid even, by editing /etc/systemd/logind.conf, and finding:

[Login]
#HandleLidSwitch=suspend
#HandleLidSwitchDocked=suspend

then uncommenting and changing to:

[Login]
HandleLidSwitch=ignore
HandleLidSwitchDocked=ignore

Then restart systemd-logind.

There are other threads pointing similar issues with suspend, for instance.

Last edited by PutridPete (2022-03-29 16:57:58)

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#7 2022-03-29 20:01:33

westlaw
Member
Registered: 2022-03-28
Posts: 4

Re: ThinkPad X270 CPU Scaling issues

Hm. Not suspending or sleeping is not really a option for me when I'm going from class to class at uni. (Even tho booting up only takes 8s with my current setup xD)

I will have a look at the thread you linked.

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#8 2022-03-31 05:40:57

PutridPete
Member
Registered: 2021-10-25
Posts: 13

Re: ThinkPad X270 CPU Scaling issues

Unfortunately, there appears to be issues in general with suspend/hibernation for certain machines. Here's yet another thread of somebody complaining of similar woes. Considering that the three of us ( you, me and the person that posted that thread) face the same issue when our laptops return from suspend or hibernation while on battery, despite having different models of Thinkpads and even running different distros, it leads me to speculate that there's probably a lingering issue somewhere between the kernel and the intel_pstate component.

I found an older thread from 2015 that also highlights this issue. Also, a bug report concerning the matter was raised for the kernel, which spawned from that thread.

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