[linux-audio-user] Can't get rid of xruns

[Dominic Sacré]

On Wednesday, 29. March 2006 17:28, Florian Schmidt wrote:
> > I did. I used various versions of 2.6.12, 2.6.15 and 2.6.16 with the
> > respective realtime patches, same result.
>
> And i suppose you also had the priorities setup similar to your current
> setup right?

At least on 2.6.15 and 2.6.16, yes (with several different versions of the 
realtime patch). I don't think I ever used chrt on a 2.6.12 kernel, 
because I hadn't read your "Ramblings on linux audio/midi system setup" 
back then :)

> The preemption check actually checks only for one class of realtime
> violations: Those where the app gives up the cpu volountarily (due to
> using non rt safe calls that consequently make the process go to
> sleep).

Ok, I see... So these xruns can only be remedied by fixing the apps, not 
by changing my system configuration?

> There's yet another class of realtime unsafeness: Simply taking too
> long in the process callback. If the period is i.e. 10 ms, and the app
> needs 20 ms you get an xrun although the app never gave up the cpu
> volountarily.

How do I catch those errors? Using the latency tracer? Or does that only 
report latencies within the kernel?
Anyway, I think I could do with some explanation how to use it, and how 
to interpret the contents of /proc/latency_trace...


    Dominic