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

William Lee Irwin III
2003-05-09T00:26:00Z

On Thu, May 08, 2003 at 06:12:12PM -0400, Chris Friesen wrote:
>>> I'm trying to test the scheduler latency on a powerpc platform. It appears
>>> that a realfeel type of program won't work since you can't program /dev/rtc
>>> to generated interrupts on powerpc. Is there anything similar which could
>>> be done?

On Thu, 8 May 2003, William Lee Irwin III wrote:
> > Why would you want to use an interrupt? Just count jiffies in sched.c

On Thu, May 08, 2003 at 05:38:23PM -0700, Davide Libenzi wrote:
> I don't know what he does mean for scheduler latency, but if it is the ctx
> switch one something like get_cycles() will be better instead of jiffies.

True, if you're looking for performance tweaks and not pathologies (which
I was) you'll need something that accurate.

-- wli