Amd-pstate-epp causing high CPU temperature in idle state

General system Kernel, boot, graphics & hardware
1

Hi, I am experiencing a higher CPU temperature with amd-pstate-epp when the PC is idle and wonder if this is a common behaviour.

Here is the scenario:

I have a Ryzen 9 5900X. When the PC boots it also starts a vmware in the background (nextcloud on debian). So when I say the PC is idle it actually means that I am logged in to gnome, have a terminal window open and the nexcloud VM is running idle in the background.

With amd_pstate=active I use scaling_governor=powersave and energy_performance_preference=balance_performance. With amd_pstate=passive I use the ondemand governor.

When I compare CPU temperature in idle state I see that amd_pstate=active is at ca. 48 °C while amd_pstate=passive stays at ca. 38 °C. I find a significant 10 degrees difference in all my tests.

When I stop the nextcloud VM, the idle temperature for amd_pstate=active drops to 36 °C (= -12 degrees). Also amd_pstate=passive drops to 36 °C (= -2 degrees) .

For amd_pstate=active it makes a very big difference if the nextcloud VM is running idle in the background. Why is that? Is that to be expected?

2

In addition I now tested the power consumption of the PC and the results are actually very surprising.

I used an energy meter " Basetech EM-3000" and here are the results:

amd_pstate                     power consumption 
                 with nextcloud VM           without nextcloud VM
active               147 W                         78 W
passive              103 W                         82 W

That tells me that background processes are a lot more intense and power demanding with amd_pstate=active. Power consumption goes up by a factor of 1,4. That pretty much makes it useless for my desktop PC.

3

have you checked with

cpupower frequency-info 
sudo turbostat

you can choose also another mode for energy_performance_preference
see on this point https://www.phoronix.com/review/amd-pstate-epp-ryzen-mobile

4

Yes, I have checked all these option. Even the setting with amd-pstate-epp powersave and energy_performance_preference=power. Regardless what I do with amd-pstate-epp, the power consumption in idle (with nextcloud vm in background) is at ca. 140 W and CPU temp is 10 degrees higher.

It seems to me that amd-pstate-epp has no good understanding about background processes. It seems like it gives CPU power to those processes like if they were foreground processes.

5

I doubt that amd-pstate-epp gives the “bad” VMware driver more control to cause the higher CPU frequency and power during idle?
I believe that passive is independent of control by the VMware driver.

6

this is coming

7

from kernel 6.14.2 and more

new energy can be used balance_performance

cpupower frequency-info
analyse du CPU 1 :
  driver: amd-pstate-epp
  CPUs which run at the same hardware frequency: 1
  CPUs which need to have their frequency coordinated by software: 1
  energy performance preference: balance_performance
  limitation matérielle : 550 MHz - 4.65 GHz
  régulateurs disponibles : performance powersave
  tactique actuelle : la fréquence doit être comprise entre 1.74 GHz et 4.65 GHz.
                  Le régulateur "powersave" est libre de choisir la vitesse
                  dans cette plage de fréquences.
  current CPU frequency: 3.33 GHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes
  amd-pstate limits:
    Highest Performance: 166. Maximum Frequency: 4.65 GHz.
    Nominal Performance: 132. Nominal Frequency: 3.70 GHz.
    Lowest Non-linear Performance: 62. Lowest Non-linear Frequency: 1.74 GHz.
    Lowest Performance: 20. Lowest Frequency: 550 MHz.
    Preferred Core Support: 1. Preferred Core Ranking: 186.