current_mhz in check_cpu_frequency always return max mhz value

[IRIX64]

Describe the bug
The output of the check_cpu_frequency command doesnt return the current mhz as expected. Instead the output is the same as MAX frequency or 100%

To Reproduce
Steps to reproduce the behavior:
Add CheckSystem = enabled to the *.ini and restart ncsp
From the command line:
[system@nagios plugins]# ./check_nrpe_32 -f check_nrpe_32.config -H host.acme.local -c check_cpu_frequency -a ''

Doesnt matter if the default if requestet or
[system@nagios plugins]# ./check_nrpe_32 -f check_nrpe_32.config -H host.acme.local -c check_cpu_frequency -a 'detail-syntax=Current MHZ:${current_mhz}'
OK: Current MHZ:2600, Current MHZ:2600|'Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz'=100%;50;30 'Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz'=100%;50;30

Expected behavior
Current MHZ which should be less than MAX MHZ as long as system isnt under heavy load

Screenshots
Return from the above:
OK: Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz: 2600/2600 MHz (100%), Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz: 2600/2600 MHz (100%)|'Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz'=100%;50;30 'Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz'=100%;50;30

System

• OS: Windows
• OS Version Windows Server 2022
• Version 0.12.6 2026-05-15

Additional context
NSclient++ runs within a vSphere 8.0.3 Virtual Machine.

[mickem]

Seems like vSphere does not report the values to the normal windows API (many performance APIs in windows is unreliable due to implementors doing different things).

Could you check if any of these counters show the correct value: VM Processor\Effective VM Speed in MHz or Processor\Host Processor Speed in MHz?

Maybe I could add an option to read from one of them instead. If they do not show reliable values either I guess the best approach would be to create a dedicated plugin for vSphere but...