Re: sudden appearance of timekeeping problems with netbsd-8 just after 8.1

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

On Tue, Jun 18, 2019 at 04:56:33PM -0000, Michael van Elst wrote:
> gdt%lexort.com@localhost (Greg Troxel) writes:
> 
> >  -timecounter: Timecounter "ACPI-Safe" frequency 3579545 Hz quality 900
> >  +timecounter: Timecounter "ACPI-Fast" frequency 3579545 Hz quality 1000
> 
> >  -timecounter: Timecounter "TSC" frequency 2800071320 Hz quality 3000
> >  +timecounter: Timecounter "TSC" frequency 3920113160 Hz quality 3000
> 
> That looks like a non-invariant TSC that changes with the "turbo" mode
> of the CPU. The interesting part is the 3.9GHz number, according to Intel
> your CPU can only go up to 3.06GHz.
> 
> 
> >I then set:
> >  kern.timecounter.hardware = hpet0
> >and things seem ok, at least after 10 minutes.
> 
> That's what to do, you can also use the ACPI timer.

I just hit the same very incorrect time on my everyday laptop which had
no issues (other than SNA artifacts ;-) )  Something must have changed...


P