Re: 2.6.14-rc3-rt10 - xruns & config questions

[Mark Knecht <markknecht@gmail.com>]

On 10/6/05, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Mark Knecht <markknecht@gmail.com> wrote:
>
> >    I am still getting a few xruns even after raising Jack's priority
> > level to 80. I am wondering whether it's fair to report these when I
> > have CONFIG_DEBUG_PREEMPT set?
>
> >   4559  78     38 [IRQ 58]
>
> >   58:     257570   IO-APIC-level  hdsp
>
> IRQ 58 is your audio interrupt, right? You should raise that one to prio
> 80 too. (via chrt)
>
> > Since my NIC is getting a higher priority than both my sound card and
> > my 1394 audio drives (IRQ217 vs. IRQ58/IRQ66) I assume that network
> > activity might possibly sometimes cause a problem? Or is this not
> > true?
>
> yeah, that could be the case.
>
>         Ingo
>

Thanks Ingo,
   I've set the HDSP priority to 80 using chrt. I'll continue to test away.

lightning ~ # ps -Leo pid,pri,rtprio,cmd | grep 58
 4559  78     38 [IRQ 58]
 8723  22      - grep 58
lightning ~ #  chrt -p 4559
pid 4559's current scheduling policy: SCHED_FIFO
pid 4559's current scheduling priority: 38
lightning ~ # chrt -p 80 4559
lightning ~ # chrt -p 4559
pid 4559's current scheduling policy: SCHED_RR
pid 4559's current scheduling priority: 80
lightning ~ #

   Can you suggest how I might be able to do this at boot time? Is
seems that the info is there but it requires figuring out the process
ID in a script and then running chrt in that script? Or is there a
simple place to configure how much priority I want to give a specific
IRQ?

   Anyway, thanks for all the help. I'll continue on. Probably I won't
see too many xruns with this set like this.

cheers,
Mark
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