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

From: Lee Revell <rlrevell@email-addr-hidden-job.com>
Date: Thu Mar 03 2005 - 19:17:39 EET

On Thu, 2005-03-03 at 17:05 +0000, Rui Nuno Capela wrote:
> 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.

Also you can't change the priority of the timer IRQ thread (IRQ 0)
anymore, because it does not run in a thread. This is not a problem.

Lee
Received on Thu Mar 3 20:15:05 2005

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