measuring avg cpu speed while powerd(8) is running
Joost Bekkers
joost at jodocus.org
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 jodocus.org
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