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Csaba Toth
Asked: 2019-03-02 16:12:55 +0800 CST

How to determine what throttles my Ryzen 7 2700 system?

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I was running a 4.18 kernel with a Ryzen 7 1700 CPU, and I upgraded to another machine which sports a Ryzen 7 2700. I carried over the whole install on the SSD drive as it is, and as far as I recall it was snappy for a few days. But then I noticed when I started to use my developer tools (IDEs, DB and cache servers, So articles open in 25 tabs in browser, ...) that the system is very sluggish. It runs well, but has a high delay 1-2 second response time under load.

Since the Ryzen 7 1700 system was usually pretty warm (70C-72C) I tried thermald. This time I uninstalled thermald (it left it's init.d script, but no thermald daemon is running now) and installed cpufreq-tools to try something for possibly enforcing different performance governors.

Right now cpufreq-info lies that the CPU is at 3.2 GHz when I set performance governor for all 16 cores. However /proc/cpuinfo tells the truth I think when it revels that the cores are running at 550 MHz (no joke, temperature is at 40C and fans are running on the lowest possible not surprisingly, I cannot hear them). When I fire up any of my IDE I want the CPU to turbo boost and I want to hear the fans spin up. Right now it's all just sluggishness.

I cannot figure out currently what holds the CPUs back. At some point I also installed https://wiki.archlinux.org/index.php/Laptop_Mode_Tools , but realized I don't want to complicate things more, it got uninstalled.

I also had some suspicion about the AMD GPU driver, but my HDMI connector had connection issues. SO I think it's most probably the CPU which causes the sluggishness with it's 550 MHz.

Also I noticed that if I leave the machine alone just for a minute or 2, the LCD dims a little bit. I have no idea which software does that dimming, but it could be the culprit, because that extremely low 1 minute threshold points towards some extreme power saving mode some daemon is trying to enforce.

power-management fan cpu amd-ryzen

1 Answers

  1. Best Answer

    Somehow the ACPI is not wired up well. upowerd / UPower (https://en.wikipedia.org/wiki/UPower) and the GUI gadgets are misinformed as well, because they just probably feed from the info found in /sys/class/power_supply/*. These sys entries show that the laptop is not plugged into the power adapter and the battery is discharging - both of these claims are obviously false.

    Follow up Questions: How can I make UPower and the power subsystem recognize that the power supply is plugged in?

    # upower -d
Device: /org/freedesktop/UPower/devices/line_power_ACAD
  native-path:          ACAD
  power supply:         yes
  updated:              Sat 02 Mar 2019 10:30:41 AM PST (17633 seconds ago)
  has history:          no
  has statistics:       no
  line-power
    online:             no

Device: /org/freedesktop/UPower/devices/battery_BAT1
  native-path:          BAT1
  vendor:               PANASONIC
  model:                AP17C5P
  serial:               1409
  power supply:         yes
  updated:              Sat 02 Mar 2019 03:24:16 PM PST (18 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               discharging
    energy:              73.2424 Wh
    energy-empty:        0 Wh
    energy-full:         74.074 Wh
    energy-full-design:  74.074 Wh
    energy-rate:         0.0195243 W
    voltage:             17.385 V
    percentage:          98%
    capacity:            100%
    technology:          lithium-ion

Daemon:
  daemon-version:  0.9.23
  can-suspend:     yes
  can-hibernate:   no
  on-battery:      yes
  on-low-battery:  no
  lid-is-closed:   no
  lid-is-present:  yes
  is-docked:       yes

    Additional verification:

    # acpi -ab
Battery 0: Discharging, 98%, discharging at zero rate - will never fully discharge.
Adapter 0: off-line

    That's also the reason why my screen dims after 120 seconds of inactivity. I'll open another question specifically for the problem.

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