Re: [LAU] Realtime, but many xruns when jack is started. Debian Etch

Hi Nigel,

see below

Florian Schmidt wrote:

>On Thursday 04 October 2007, Nigel Henry wrote:
>
>
>
>>>>Ok, you have not done any irq priority tuning.. Try setting the IRQ-10
>>>>process [your emu10k1] to prio 90..
>>>>
>>>>
>>>I'm not sure what I'm doing here. I presume I need to use chrt to change
>>>the priority, but am not sure of the correct syntax. The current pid for
>>>IRQ10 is 940.
>>>
>>>Could you give me a line that will work for this pid, as the man page is
>>>pretty hopeless with no examples, and about 3 hrs of googling turned up
>>>virtually nothing.
>>>
>>>Many thanks.
>>>
>>>Nigel.
>>>
>>>
>>>
>>>>Flo
>>>>
>>>>
>>Bad to reply to my own post, but I've resolved the problem.
>>
>>
>
>I never quite understood what was supposed to be bad about replying to one's
>own post.. :)
>
>
>
>>One xrun after 6m 33secs of 0.253 msecs, which is what I'm getting on
>>Fedora 7.
>>
>>
>
>With soundcard irq prio at 90 [not shared with any other device], Jack prio at
>70 and all other irq prios at default 51?
>
>Then it's either an application bug [are you running any applications]? Or a
>bug in the emu10k1 driver. Or in jackd, though i suppose that's rather
>unlikely..
>
>
>
>>Will that change of priority I've made for the soundcard on the current
>>pid, hold after a reboot?
>>
>>
>
>Nope.. It will be started with the default prio again. Have a look at the
>rtirq script or fiddle your own initscript. Most distros have some "local"
>init script where you put that command..
>
>Flo
>
>
Nigel,

This will tell you which IRQ your sound card is on:
cat /proc/interrupts | grep -i emu10k1

Then use this line to set the rtprio value (90 in this example) of that
IRQ (obviously, replace the xx with your actual IRQ value). Assuming
this IRQ is stable across reboots, put this line in /etc/rc.local on
Fedora systems. Been working well here for a long time.
chrt -f -p 90 `pidof "IRQ-xx"`

If some shell scripting guru wants to jump in, I'm sure there is a way
to connect these two lines so that the emu10k IRQ is found at boot time
(so this removes the requirement that your sound card always gets the
same IRQ).

HTH,
Rick

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Received on Thu Oct 4 20:15:03 2007