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#1 2021-06-26 21:24:30

Compizfox
Member
Registered: 2015-08-06
Posts: 16

Is my laptop idling correctly? (high power draw)

I'm running Arch on my Thinkpad T14 (Ryzen Pro 4650U), and I am unsure about its power usage.

I get about 3 to 4 hours of battery life, which seems to low. According to powertop, the power usage usually is between 10 and 14 W in idle (with the backlight at 50%).

What can I do to lower this? I already have TLP installed and running.

What seems strange to me, is that the CPU clock never goes lower than 1.4 GHz. This seems to be the hardware limit, as reported by cpupower:

analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 1.40 GHz - 2.10 GHz
  available frequency steps:  2.10 GHz, 1.70 GHz, 1.40 GHz
  available cpufreq governors: conservative ondemand userspace powersave performance schedutil
  current policy: frequency should be within 1.40 GHz and 1.40 GHz.
                  The governor "schedutil" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 1.65 GHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: no

I also do not have any C-states higher than C3. Is this normal?

CPUidle driver: acpi_idle
CPUidle governor: menu
analyzing CPU 0:

Number of idle states: 4
Available idle states: POLL C1 C2 C3
POLL:
Flags/Description: CPUIDLE CORE POLL IDLE
Latency: 0
Usage: 23448
Duration: 830232
C1:
Flags/Description: ACPI FFH MWAIT 0x0
Latency: 1
Usage: 503697
Duration: 61253352
C2:
Flags/Description: ACPI IOPORT 0x414
Latency: 400
Usage: 0
Duration: 0
C3:
Flags/Description: ACPI IOPORT 0x415
Latency: 350
Usage: 748264
Duration: 2681505492

Last edited by Compizfox (2021-06-26 21:30:06)

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#2 2021-06-27 11:31:08

Sin-H
Member
Registered: 2010-10-25
Posts: 12

Re: Is my laptop idling correctly? (high power draw)

I logged in to the BBS today specifically to report on a similar issue I had. Maybe this can help you.

I have Arch with sway running on a T14s with AMD Ryzen Pro 7 4750U, and for the past 10 days (I've only had the laptop for 10 days) my power consumption with a browser and some terminals open was at about 4-6W (at low backlights of about 10%), giving me ~10hrs of battery life on my 57Wh battery, which is satisfying. I did not even have TLP running.

Yesterday after upgrading my kernel from 5.12.12.arch1-1 to 5.12.13.arch1-1 as well as mesa from 21.1.2-1 to 21.1.3-1, I noticed my power consumption went up to 10-14W even with backlight at its lowest setting.

After I couldn't find anything that had changed in other packages, I tried all possible combinations of versions of linux, amdvlk, vulkan-radeon, libva-mesa-driver, and in the end it turns out that the kernel upgrade was the culprit.

- using amdvlk instead of vulkan-radeon improved my power consumption in tty but not in wayland;

- using linux-5.12.12 gives me back my ~5W power consumption, no matter which version of mesa and which vulkan driver I use.

What's weird is I also installed the lts kernel (5.10.46-1) while playing around, and it has the same power drain problem. This makes me suspect that the culprit must be some patch that was applied to both linux and linux-lts very recently. The changelogs ( https://lwn.net/Articles/860654/ and https://lwn.net/Articles/860655/ ) seem to hint that it was the recent changes in amdgpu/gfx that introduced this power drain.

TL;DR: try downgrading your kernel to 5.12.12, that's what helped me, maybe it helps you too.


Compizfox wrote:

I also do not have any C-states higher than C3. Is this normal?

This is the case for me too, I only have 1.4 GHz, 1.6 GHz and 1.7 GHz as frequencies. Ryzens seem to not go as low in their frequencies as Intels. Furthermore, it appears the boost states are simply not reported correctly by cpupower: https://bbs.archlinux.org/viewtopic.php?id=266285

Last edited by Sin-H (2021-06-27 13:06:53)

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#3 2021-06-27 13:01:31

magillos
Member
Registered: 2010-07-03
Posts: 29

Re: Is my laptop idling correctly? (high power draw)

Same issue with Ryzen 5 5500U. I noticed it first with 5.12.13 version of linux-ck-zen2 and I initially thought it's a problem with that particular kernel. But yesterday I upgraded Arch kernel to 5.12.13 and the same happened. Downgrading to 5.12.12 fixes it.

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#4 2021-06-27 14:17:50

Compizfox
Member
Registered: 2015-08-06
Posts: 16

Re: Is my laptop idling correctly? (high power draw)

Thank you both for your replies!

Linux 5.12.13 indeed seems to be the culprit. After downgrading to 5.12.12, the power consumption is reduced to ~6 W.

Very strange. I'll try if I can find a kernel bug report related to this.

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#5 2021-06-27 14:20:25

Sin-H
Member
Registered: 2010-10-25
Posts: 12

Re: Is my laptop idling correctly? (high power draw)

Compizfox wrote:

I'll try if I can find a kernel bug report related to this.

I was looking around to see if someone had filed anything yet, and while our problem was not in there, some other related problems with amdgpu were, and the change introduced in 5.10.46 and 5.12.13 will be reverted as it seems:

https://lists.freedesktop.org/archives/ … 65612.html

"may cause some APUs fail to enter gfxoff in certain user cases." also sounds like it could lead to higher power usages.

Last edited by Sin-H (2021-06-27 14:22:09)

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#6 2021-06-27 14:27:47

Compizfox
Member
Registered: 2015-08-06
Posts: 16

Re: Is my laptop idling correctly? (high power draw)

Sin-H wrote:
Compizfox wrote:

I'll try if I can find a kernel bug report related to this.

I was looking around to see if someone had filed anything yet, and while our problem was not in there, some other related problems with amdgpu were, and the change introduced in 5.10.46 and 5.12.13 will be reverted as it seems:

https://lists.freedesktop.org/archives/ … 65612.html

"may cause some APUs fail to enter gfxoff in certain user cases." also sounds like it could lead to higher power usages.

Good find! I agree, that appears to be the cause.

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#7 2021-06-27 16:19:07

magillos
Member
Registered: 2010-07-03
Posts: 29

Re: Is my laptop idling correctly? (high power draw)

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