Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.6.9

[Ingo Molnar <mingo@elte.hu>]

* Rui Nuno Capela <rncbc@rncbc.org> wrote:

> OK. Already tested RT-V0.6.9 and things are really good, so far. Got
> it under the jackd-R + 9*fluidsynth workload test, and the comparison
> to 2.6.9 (vanilla) is getting kind of humiliating :)
> 
>                                    2.6.9   RT-V0.6.9
>                                  --------- ---------
>  XRUN Rate   . . . . . . . . . :    415         0    /hour
>  Delay Rate (>spare time)  . . :    493         0    /hour
>  Delay Rate (>1000 usecs)  . . :    913         1    /hour
>  Delay Maximum . . . . . . . . :   6877       864    usecs
>  Cycle Maximum . . . . . . . . :   1440      1552    usecs
>  Average DSP Load. . . . . . . :     38.9      40.5  %
>  Average Interrupt Rate  . . . :   1337      1338    /sec
>  Average Context-Switch Rate . :   7488      9048    /sec

cool, good numbers. May i have a stats suggestion for future runs? Could
you monitor the system (kernel) CPU overhead and userspace overhead as
well?

> As before, these stats were taken by running jackd -v -dalsa -dhw:0
> -r44100 -p128 -n2 -S -P, loaded with 9 (nine) fluidsynth instances, on
> a P4@2.533Ghz laptop, against the onboard sound device (snd-ali5451).
> The results were averaged for 12 consecutive runs of 5 minutes each.
> 
> On the RT kernel, the IRQ 5 handler thread, that serves the ali5451
> sound device, has been chrt'ed to SCHED_FIFO and to priority=60 (chrt
> -p -f 60 `pidof "IRQ 5"`). This time thought, I haven't touched the
> ksoftirqd/0 scheduling policy nor priority.
> 
> I am also rehearsing these same tests on my P4/SMT desktop. I'll post
> those a bit later today.
> 
> As a personal comment, I've never, never seen so good figures in any
> other kernel I've came across in the last couple of years. I hope this
> can only go to the better ;)

i hope so too :) There's no reason why the performance of the current
-RT kernel couldnt be maintained, there are no corners cut.

	Ingo