Sensors plugin generates a peak of CPU consumption

[nicolargo]

1. Run Glances with the sensor plugin enabled: every 3 refreshs a peak of Glances process CPU is observed.
2. Run Glances with the sensor plugin disabled: no CPU peak observed.

Note: the peak every "3 refreshs" is related to the following key in the sensors code:

# Define the default refresh multiplicator
# Default value is 3 * Glances refresh time
# Can be overwritten by the refresh option in the sensors section of the glances.conf file
DEFAULT_REFRESH = 3

The goal is to understand why the CPU peak is so high (from 5% to 11% on my system).

[nicolargo]

A specific branch (issue2851) has been created with a specific test script (test-data/issues/issue2851.py):

./venv/bin/python ./test-data/issues/issue2851.py 
Init Glances to make the stats more relevant (wait 6 seconds)
CPU consumption with sensors plugin disable
1/6: 0 sensor
2/6: 0 sensor
3/6: 0 sensor
4/6: 0 sensor
5/6: 0 sensor
6/6: 0 sensor
CPU consumption with sensors plugin disable: 5.8
CPU consumption with sensors plugin enable
1/6: 9 sensors
2/6: 9 sensors
3/6: 9 sensors
4/6: 9 sensors
5/6: 9 sensors
6/6: 9 sensors
CPU consumption with sensors plugin enable: 8.3

[nicolargo]

After a quick analyse, the peak (between 2 and 3% of a CPU core) came from the calls to psutil.sensors_temperatures() and psutil.sensors_fans().

[eric72777]

I don't know if it's related to this issue, but I noticed significantly higher CPU usage on recent versions of glances.

I've noticed this on multiple machines, but it's currently running on Docker version 25.0.6.

Old version with good CPU usage:

  glances:
    container_name: glances
    environment:
      - GLANCES_OPT=-w --disable-check-update --time 2 --disable-plugin amps,containers,processcount
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    pid: host
    network_mode: host
    image: docker.io/nicolargo/glances:3.4.0.5-full
    restart: unless-stopped

Newer version with high CPU usage:

  glances:
    container_name: glances
    environment:
      - GLANCES_OPT=-w --disable-check-update --time 2 --disable-plugin amps,containers,processcount
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    pid: host
    network_mode: host
    image: docker.io/nicolargo/glances:latest #4.1.2.1
    restart: unless-stopped