FreeBSD sound distortion problems with SB Live! fixed with PREEMPTION

[Thomas-Martin Seck]

* Doug White <dwhite at gumbysoft.com>:

> I played a 160kb VBR MP3 with mpg321 (mpg123 was compiled to use esound on
> this system so I decided to try something not so polluted) direct to each
> card in turn with a -j3 buildworld running in the background, using the
> same disk as the MP3s were located on.  I ran the buildworld in a Konsole
> window on KDE 3.2.3 and played the mp3's in another.
> 
> I start getting wierdness when the load average hits 5+ with 0% idle.
> Otherwise things hold up.

Please test what happens when you produce really heavy disk activity in
the background; untarring firefox or Xorg should be sufficient.

> If you are getting distortion on an otherwise idle system I'll be more
> interested, although that doesn't appear to be the case...

Heavy ATA activity is sufficient for me, see my earlier post in this
thread (I run RELENG_5 with the 4BSD scheduler, no WITNESS. PREEMPTION
is enabled which seems to help a bit). pcm0 is on its own on irq 5.