What is tmon and how can I use it?

Question

I found a tmon utility in my CentOS 7.5 and I've googled that:

TMON is conceived as a tool to help visualize, tune, and test the complex thermal subsystem.

...

For monitoring only:

$ sudo ./tmon

https://github.com/torvalds/linux/tree/master/tools/thermal/tmon

But as a result of the launch, I only get an error:

No thermal zones found, exit

on my E5-2620 v4 and kernel 3.10.0-862.11.6.el7.x86_64.

I also found other poor mentions and similar topics (e.g. this one on RH: https://bugzilla.redhat.com/show_bug.cgi?id=1466991) but it's not cleared up how to use it for monitoring properly and what do this "zones" mean.

UPD This CentOS is on baremetal server.

Maybe stating the obvious, but for starters that will only have a chance of working on bare-metal servers and probably won't work on a VPS. — HBruijn, Feb 01 '19 at 09:56

score 1 · Accepted Answer · answered Feb 01 '19 at 13:35

You probably need to load certain kernel modules for your motherboard to get thermal zones readings, the following is a reading from an Ubuntu 14.04 LTS bare-metal server using lm-sensors package

root@vm02:~# sensors
coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +64.0°C  (high = +80.0°C, crit = +100.0°C)
Core 0:         +64.0°C  (high = +80.0°C, crit = +100.0°C)
Core 1:         +60.0°C  (high = +80.0°C, crit = +100.0°C)
Core 2:         +62.0°C  (high = +80.0°C, crit = +100.0°C)
Core 3:         +58.0°C  (high = +80.0°C, crit = +100.0°C)

nct6776-isa-0290
Adapter: ISA adapter
Vcore:          +0.86 V  (min =  +0.00 V, max =  +1.74 V)
in1:            +1.85 V  (min =  +0.00 V, max =  +0.00 V)  ALARM
AVCC:           +3.34 V  (min =  +2.98 V, max =  +3.63 V)
+3.3V:          +3.33 V  (min =  +2.98 V, max =  +3.63 V)
in4:            +0.91 V  (min =  +0.00 V, max =  +0.00 V)  ALARM
in5:            +1.75 V  (min =  +0.00 V, max =  +0.00 V)  ALARM
in6:            +0.87 V  (min =  +0.00 V, max =  +0.00 V)  ALARM
3VSB:           +3.49 V  (min =  +2.98 V, max =  +3.63 V)
Vbat:           +3.33 V  (min =  +2.70 V, max =  +3.63 V)
fan1:             0 RPM  (min =    0 RPM)
fan2:          1912 RPM  (min =    0 RPM)
fan3:             0 RPM  (min =    0 RPM)
fan4:             0 RPM  (min =    0 RPM)
fan5:             0 RPM  (min =    0 RPM)
SYSTIN:         +37.0°C  (high =  +0.0°C, hyst =  +0.0°C)  ALARM  sensor = thermistor
CPUTIN:         +36.0°C  (high = +80.0°C, hyst = +75.0°C)  sensor = thermistor
AUXTIN:         +32.0°C  (high = +80.0°C, hyst = +75.0°C)  sensor = thermistor
PECI Agent 0:   +63.0°C  (high = +80.0°C, hyst = +75.0°C)
                         (crit = +100.0°C)
PCH_CHIP_TEMP:   +0.0°C
PCH_CPU_TEMP:    +0.0°C
PCH_MCH_TEMP:    +0.0°C
intrusion0:    ALARM
intrusion1:    ALARM
beep_enable:   disabled

you can use the lm-sensors package to identify which modules you need to load, check man sensors-detect

lm_sensors is not required to use tmon. I use it on systems without sensors installed. If you don't see thermal zones, you probably need a newer kernel. — Michael Hampton, Feb 01 '19 at 13:55
I did not state that one needs lm_sensors to use tmon, its just a good package that makes life easier. — Zaid Amireh, Feb 01 '19 at 19:43

What is tmon and how can I use it?

1 Answers1