[LAD] 2.6.20 scheduler and buffer underruns

[Juuso Alasuutari]

On Thursday 12 July 2007 20:23:02 Lee Revell wrote:
> On 7/12/07, Darren Gibbs <tsquank at yahoo.com> wrote:
> > So the story is more interesting now... with SCHED_FIFO I'm seeing
> > occational delays of about 60 sample frames (@44K) when there is very
> > little other CPU activity.  It still looks like a buffer underrun in
> > that the audio data is contiguous on both sides of the delay, so I'm
> > not dropping a buffer.  When I load the CPU with another task doing a
> > while(1) loop, the glitches go away.  Hmmm....
>
> You will probably need to run an -rt patched kernel to get acceptable
> performance from JACK.  This also includes a cool latency tracing
> feature that will tell you what IRQ handler is using too much CPU
> time.

Joining in on this discussion. What feature is this, and how does one use it? 
I need to diagnose my system for the source of constant XRUNs.

Juuso