[ardour-users] Xrun - Aaarrrgghhh!!

[Jason Jones]

Alexander wrote:

>Hi all!
>
>[ sorry for my english, i'm brazilian ]
>
>I have one Debian with 2.6.8 kernel, Atlhon 2.2, 256MB RAM and HD with 40GB.
>
>Hard disk have 50MB/sec of transfer rate.
>
>Jackd is 0.98.8
>
>And I have a LOT of xruns!!!!
>
>Somebody tell me about one patch. But I don't have any idea if it's realy necessary or where can I find this patch and how configure options of this patch.
>
>Somebody can help me???!!!!
>
>Wath's happen with jackd?!
>
>In kernel 2.4 is all fine!
>
>Now I have one big problem because tomorrow I need record some songs of pupils in school!! And I don't have machines with 2.4 kernel.
>
>And it's impossible record with that xruns!
>
>Thanks for any help!
>Alexander Franca
>Brazil - Rio de Janeiro
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>ardour-users-ardour.org mailing list
>ardour-users at lists.ardour.org
>http://lists.ardour.org/listinfo.cgi/ardour-users-ardour.org
>
>
>  
>
I had the exact same problem, Alexander.  You can find the whole 
discussion on www.gmane.org (direct link is: 
http://news.gmane.org/gmane.comp.audio.jackit/cutoff=8321 )

I solved it by following the advice found below by someone named "Lee".

Here's the reply.

The 2.4 low latency kernel is the time-tested solution, this is what you
should use if you need to get real audio work done now.

The 2.6 low latency kernel (aka Ingo's voluntary preemption patches)
will work better than 2.4, but it is not 100% stable yet.

If you want to try the new 2.6 low latency kernel, here is a QuickStart:

Start with:

    http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.8.tar.bz2

Then apply these patches in this order:

    http://kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.9-rc1.bz2
    http://redhat.com/~mingo/voluntary-preempt/patch-2.6.9-rc1-bk12.bz2 <http://redhat.com/%7Emingo/voluntary-preempt/patch-2.6.9-rc1-bk12.bz2>
    http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.9-rc1-bk12-R9 <http://redhat.com/%7Emingo/voluntary-preempt/voluntary-preempt-2.6.9-rc1-bk12-R9>

This will give you the irq threading settings in /proc that other posters referred to.

Please keep in mind that this is not completely stable yet, I would not
recommend it for production use, but it works very well for many
people.  You are likely to have better results on a regular 32 bit
single processor (that means no hyperthreading) x86 desktop system,
because this has been well tested.

Lee



I followed his advice to the tee (except I installed the 2.6.8.1 kernel 
instead of the 2.6.8 one), and it worked like a charm.  I'm now 
recording 32bit, 44.1K recordings with as low as 5ms latency with 0 xruns.

Hope this helps.

--Jason

PS - you might want to read that whole thread along with the beginning 
threads of the "Cannot get rid of XRUNS in ardour" thread.  There are 
also some posts in the ardour mailing list which helped me understand a 
lot about what hardware can cause xruns.  That thread is named "New User 
/ Problems" (in the user list, not the dev one)

Happy reading!