Checking CPU temperature

Publication Date: 20 Jan 2023

1 Environment #

This document applies to the following products and product versions:

SUSE Linux Enterprise Server 15 SP3, 15 SP2, 15 SP1, 15 GA, 12 SP5, 12 SP4, 12 SP3
SUSE Linux Enterprise Server for SAP Applications 15 SP3, 15 SP2, 15 SP1, 15 GA, 12 SP5, 12 SP4, 12 SP3
SUSE Linux Enterprise High Availability Extension 15 SP3, 15 SP2, 15 SP1, 15 GA, 12 SP5, 12 SP4, 12 SP3
SUSE Linux Enterprise High Performance Computing 15 SP3, 15 SP2, 15 SP1, 15 GA
SUSE Linux Enterprise Desktop 15 SP3, 15 SP2, 15 SP1, 15 GA, 12 SP5, 12 SP4, 12 SP3
SUSE Linux Enterprise Real Time 15 SP3, 15 SP2, 15 SP1, 15 GA, 12 SP5, 12 SP4, 12 SP3

2 Introduction #

Keeping track of CPU temperature has several benefits.

Energy savings and cost reduction. If all your CPUs are running at full speed, it takes much more energy than if they are idling. Also cooling down CPUs is a critical cost factor, especially in data centers.
Identifying unwanted processes that takes too much CPU power. This can be a program going “wild” due to a software problem, or when a process occupies a CPU for too long time. Identifying such processes help to free your CPU resources from being unavailable and keep CPU responsive.
Better protection of the CPUs and the hardware. CPUs has a thermal protection when the CPU gets too warm. This protects it from overheating. However, if a CPU temperature reaches 80°C or higher, it is a warning sign that something is wrong. It can be that a fan is dead, the cooling system does not work properly, or the thermal paste wasn't applied correctly.
A long-term reduction of the carbon footprint can be achieved by adjusting the cooling parameters.

Follow the instruction below to learn how to monitor your CPU temperature.

3 Requirements #

Root permissions to install the required package
The package sensors

4 Preparing the hardware sensors #

Before you can measure the CPU temperature, check what hardware sensors are available in your computer:

Install the required package:
```
zypper install sensors
```

To detect all the sensors in your system, run the following command as root:

# sensors-detect

When prompted to detect specific hardware monitoring chips, accept the default answer is YES by pressing . At the end, the script shows a summary of what chips were detected:

Now follows a summary of the probes I have just done.

Driver `coretemp':
  * Chip `Intel digital thermal sensor' (confidence: 9)

Driver `to-be-written':
  * ISA bus, address 0xa40
    Chip `ITE IT8686E Super IO Sensors' (confidence: 9)

Do you want to generate /etc/sysconfig/lm_sensors? (YES/no):

Confirm to generate the file /etc/sysconfig/lm_sensors. After confirmation, the script creates a systemd service (/usr/lib/systemd/system/lm_sensors.service.) that is enabled by default.

Check the status of the systemd service:

sudo systemctl status lm_sensors
● lm_sensors.service - Initialize hardware monitoring sensors
   Loaded: loaded (/usr/lib/systemd/system/lm_sensors.service; enabled; vendor preset: disabled)
   Active: active (exited) since Fri 2021-09-10 16:57:55 CEST; 2min 23s ago
  Process: 32552 ExecStart=/usr/bin/sensors -s (code=exited, status=0/SUCCESS)
  Process: 32551 ExecStart=/sbin/modprobe -qab $BUS_MODULES $HWMON_MODULES (code=exited, status=0/SUCCESS)
 Main PID: 32552 (code=exited, status=0/SUCCESS)
    Tasks: 0
   CGroup: /system.slice/lm_sensors.service

Sep 10 16:57:55 edison systemd[1]: Starting Initialize hardware monitoring sensors...
Sep 10 16:57:55 edison systemd[1]: Started Initialize hardware monitoring sensors.

After you have completed these steps, your computer has detected all sensors and has started to monitor them.

5 Getting real-time temperature data #

To obtain a snapshot of your current temperature, run the following command:

> sensors
[...]
Adapter: ACPI device
temp1:        +16.8°C  (crit = +18.8°C)
temp2:        +27.8°C  (crit = +119.0°C)
temp3:        +29.8°C  (crit = +119.0°C)

nvme-pci-0700
Adapter: PCI adapter
Composite:    +36.9°C  (low  = -273.1°C, high = +83.8°C)
                       (crit = +83.8°C)
Sensor 1:     +36.9°C  (low  = -273.1°C, high = +65261.8°C)
Sensor 2:     +43.9°C  (low  = -273.1°C, high = +65261.8°C)

coretemp-isa-0000
Adapter: ISA adapter
Package id 0:  +43.0°C  (high = +82.0°C, crit = +100.0°C)
Core 0:        +41.0°C  (high = +82.0°C, crit = +100.0°C)
Core 1:        +41.0°C  (high = +82.0°C, crit = +100.0°C)
Core 2:        +43.0°C  (high = +82.0°C, crit = +100.0°C)
Core 3:        +41.0°C  (high = +82.0°C, crit = +100.0°C)
Core 4:        +41.0°C  (high = +82.0°C, crit = +100.0°C)
Core 5:        +40.0°C  (high = +82.0°C, crit = +100.0°C)

Run the command below to monitor temperature in real time:

> watch sensors