Re: Cyclictest expected results

[Robert Schwebel <r.schwebel@pengutronix.de>]

On Sun, Sep 30, 2007 at 09:07:19PM +0530, Jaswinder Singh wrote:
> Here are my results on Intel Pentium 4 :
>
> Command line :  ./cyclictest -t 1 -p 80 -i 10000 -l 10000 -q

Can you post the output of /proc/timer_list?

> 2.6.23-rc8-rt1 :
> WARNING: High resolution timers not available
> T: 0 ( 2003) P:80 I:10000 C:  10000 Min:   1500 Act: 6129 Avg: 4502 Max:    7832

That one should give you sane results.

> From where I can get Linux-2.6.16-hrt5 and Linux-2.6.16-rt12 patches.

I don't think it makes much sense to play with such an old kernel any more.

> CONFIG_HIGH_RES_TIMERS=y are defined in .config then why I am getting
> "WARNING: High resolution timers not available".
>
> Why my results are not so impressive in realtime even though I defined:
> CONFIG_PREEMPT_RT=y
> CONFIG_PREEMPT=y
> CONFIG_PREEMPT_SOFTIRQS=y
> CONFIG_PREEMPT_HARDIRQS=y
> CONFIG_PREEMPT_BKL=y

Doesn't look too bad. Are you sure you actually _bootet_ that kernel? :)

> Min, Avg and Max are showing cyclic latencies. Ideally It should be
> ZERO. Am I right ?

You won't get zero. On x86 these latencies should be well below 100 us
maximum time, with an average in the lower 10 us range.

Robert
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