100ms is just the refresh rate of ActivityMonitor by default. So with ActivityMonitor we can’t see anythin that’s happening faster than that. What are you even talking about?
Are we into personal attack now? I’m not really interested in that.
I will continue pointing to the code, which you apparently understand.
In the case of “computing load by the CPU itself”, I was referring to the MPREF and APERF MSRs, which are read here: intel_pstates.cpp « intel_pstates « cpufreq « power « kernel « add-ons « src - haiku - Haiku's main repository and give info on the number of CPU cycles executed, from which you can detect the CPU frequency, and if the CPU was shut down for powersaving.
I have, of course, oversimplified things in this forum thread to give a simple and understandable response to an user that isn’t necessarily well-versed into CPU internals. If you do understand the code, maybe you can go and read it instead of me having to do the research for you, it will save a lot of time and frustration.