Re: [linux-audio-user] Graphics card an realtime performance

On Tue, Feb 07, 2006 at 10:06:46PM +0100, Florian Schmidt wrote:
> > Hi all,
> >
> > Could a better graphics card result in better realtime performance? I can
> > get a good realtime performance on my box (buffersize 64 and less) but
> > when using X some display activity seems to cause xruns. E.g sooperlooper
> > is far more usable without it's gui.
> >
> > This is on a pentium3 600Mhz PC, running gentoo kernel 2.6.14 with rt22
> > patch applied. I also prioritize the irq's as documented on this list. The
> > graphics card is a Nvidia Vanta LT with 16 Mb memory.
>
> What software do you use? I assume JACK? If so, setting up the irq's is
> not enough. You also need to run jackd with the right prio (below
> soundcard irq, but above all others)
>
> See
>
> http://tapas.affenbande.org/?page_id=40
>
> for a little more exhaustive info.

Yes, i use jack. I also use the rtirq package. Here is the relevant
info:

reus ~ # cat /proc/interrupts
           CPU0
  0: 1009634 XT-PIC [........N/ 0] pit
  1: 727 XT-PIC [........./ 0] i8042
  2: 0 XT-PIC [........N/ 0] cascade
  4: 0 XT-PIC [........./ 0] Serial MIDI
  5: 1661 XT-PIC [........./ 0] eth0
  8: 2 XT-PIC [........./ 0] rtc
  9: 1 XT-PIC [........./ 0] acpi, ICE1712
 10: 121 XT-PIC [........./ 0] uhci_hcd:usb1, EMU10K1
 12: 3651 XT-PIC [........./ 0] i8042
 14: 4926 XT-PIC [........./ 0] ide0
 15: 653 XT-PIC [........./ 0] ide1

reus ~ # /etc/init.d/rtirq status
 * status: started

  PID CLS RTPRIO NI PRI %CPU STAT COMMAND
  200 FF 80 - 120 0.0 S< IRQ 8
   14 FF 70 - 110 0.0 S< IRQ 9
  262 FF 60 - 100 0.0 S< IRQ 10
  277 FF 50 - 90 0.0 S< IRQ 1
  206 FF 49 - 89 0.0 S< IRQ 12
  209 FF 46 - 86 0.0 S< IRQ 6
  240 FF 45 - 85 0.0 S< IRQ 14
  242 FF 44 - 84 0.0 S< IRQ 15
 6472 FF 41 - 81 0.0 S< IRQ 5
 6635 FF 40 - 80 0.0 S< IRQ 4

Not exactly the same numbers as yours, but it looks ok to me.
I was trying to avoid the route Lee mentions, debugging using the
latency tracer, but it looks like i have to find some time to study
it. Anyway, thanks a lot all of you for your input, i will let you know
when i have made some progress.

-- 
gerrit