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

From: Roland Dreier (roland@topspin.com)
Date: Thu May 08 2003 - 23:13:09 EST


    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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Thu May 15 2003 - 22:00:30 EST