measuring avg cpu speed while powerd(8) is running

Joost Bekkers joost at
Sun Aug 7 08:11:20 GMT 2005

On Sat, Aug 06, 2005 at 07:33:02PM +0200, Philip S. Schulz wrote:
> Joost Bekkers wrote:
> >
> >Is there a way to calculate (over eg. a 5 minute interval) the average 
> >amount the cpu was throttled? In this case by powerd(8).
> No, powerd currently reads the CPU usage periodically and adjusts the 
> clock speed based on the current CPU idle value. You can somewhat 
> influence the behavior with the options described in the powerd man page.
>  powerd does not keep a history of CPU usage and it does not record the 
> adjustments it makes. However, you could kind of record powerd 
> activities by starting it with the -v option and redirect stdout to a file.

Perhaps I should have said that differently: it is being throttled by powerd.
It doesn't have to do the measuring of the average itself.

> >I was thinking there might be a counter/timer which is linked to the cpu 
> >clock, but sofar I haven't been able to find one.
> Well, you can see the current CPU frequency by looking at dev.cpu.0.freq 
> where 0 is the id of the CPU you want to query.

At the times I take measurements the cpu tends to run at 100%, which would
result in a nice flat line.

greetz Joost
joost at

More information about the freebsd-questions mailing list