Re: how to measure scheduler latency on powerpc? realfeel doesn't work due to /dev/rtc issues

Roland Dreier
2003-05-09T04:00:35Z

Chris> I want to find an additional programmable interrupt source.
Chris> It bites that cheap PCs have this, and the powerpc doesn't.

I don't know which PowerPC CPU you are using, but for example the IBM
4xx series (and all Book E processors) have a "fixed interval timer"
interrupt that is currently not used at all by Linux. (The
"programmable interval timer" is used to increment jiffies)

On something like the Motorola 74xx, you might be able to use the
something like the performance monitor to generate an exception.

Best,
Roland