[linux-audio-user] Re: Dual Core?

[David Causse]

Oe Thu, Nov 16, 2006 at 11:11:01AM +0100, Julian Hagenauer wrote:
> 
> Hi,
> thank you for your answer.
> rlimits seem to work, becasue i got the same results as mentioned above.
> In fact i have a Centrino Duo (Dual Core) notebook, so this might be the reason fpr my xruns and stuttering sound?
> If i run jackd -h i got no option mention --clocksource.
> What can i do next?

In fact when I had problems related to tsc clock drift I had this type
of errors : 

delay of XXX usecs exceeds estimated spare time of YYY; restart ...

If this is your case you have to upgrade jackd, I'm afraid there is no
simple way to do so. You'll have to compile yourself jack 0.102.20.

If you have only :

**** alsa_pcm: xrun of at least 1.105 msecs

Here what I would check first :

1) Your audio card is not reliable
Some cards have a fixed sample rate, just try to launch jackd with other
sample rate. Did you check the card matrix on
http://www.alsa-project.org to check if other people experienced the
same problem?

2) Some issues with laptop
I have seen very weird things with laptop. And I can't help here, I
don't own a laptop... For example, can you see noticeable difference
when your laptop is on AC Mains and on battery?

3) other process is running and do heavy load? check top and identify
it.

4) Your kernel config
check your PREEMPT config with 
zcat /proc/config.gz | grep CONFIG_PREEMPT
If you have CONFIG_PREEMPT_NONE=y
It is not very good for real-time audio you need at least
CONFIG_PREEMPT_DESKTOP=y
If you are not confident with kernel compilation I won't be able to help
because I don't know where you can find such precomiled kernel for
debian testing.
But if you have xruns at 1024/2 frames I'm not sure it will help...

Well I have no more clue, there is a solution somewhere don't give up :)

Good luck

David.