Re: [linux-audio-user] USX2Y rawusb mode

From: Rui Nuno Capela <rncbc@email-addr-hidden>
Date: Thu Mar 03 2005 - 19:05:03 EET

Spencer,
>
> Rui said a while ago that he was getting a similar message, until
> he tuned the IRQ priorities, but I've been googling around and I
> can't figure out how to do it. I tried
> chrt -f -p 90 'pidof "IRQ 0"'
> as directed on some website, but it just returns
>
> execvp: No such file or directory
> failed to execute pidof "IRQ 0"
>

When I said that I was assuming that you have Ingo Molnar's
realtime-preempt patch, which applies to vanilla 2.6 kernels only (latest
is 2.6.11-rc4). The patch is here:
  http://people.redhat.com/~mingo/reatime-preempt/
You can only do that IRQ tunning if you have this kernel configured with
PREEMPT_RT=y (i.e. complete realtime-preemption enabled).

Once you have this up and running, tune the IRQ threads (with chrt) like
this example:

  timer: chrt -f -p 90 `pidof "IRQ 0"`
  rtc: chrt -f -p 80 `pidof "IRQ 8"`
  snd: chrt -f -p 70 `pidof "IRQ 5"`
  usb: chrt -f -p 60 `pidof "IRQ 10"`

Please note you must check which IRQ numbers are the appropriate (cat
/proc/interrupts); the above is just an example taken from my laptop,
where the USB controller (ohci_hcd) is on IRQ 10 and the onboard sound is
on IRQ 5. YMMV.

Bye.

-- 
rncbc aka Rui Nuno Capela
rncbc@email-addr-hidden
Received on Thu Mar 3 20:15:05 2005

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