Sound performance problems in FreeBSD

Suleiman Souhlal ssouhlal at
Wed Sep 8 23:48:04 PDT 2004


On Sep 5, 2004, at 5:56 AM, Markus Hästbacka wrote:

> Hello list, I've experienced sound performance issues from the very 
> first day I tested 5.x. The problem was that sound skipped whatever I 
> did. Now I've reduced the problem a bit with changing my kernel config 
> (No, any debug option isn't on or haven't ever been on when I've 
> tested sound performance). After I recompiled the new kernel the sound 
> didn't skip anymore, but now after 10 hour uptime and 5 hours of mp3 
> playing the skipping is back. The skipping is like every second 
> there's a weird noise if I listen to something, like the track would 
> go slower for 2/10 seconds of every second, you can imagine how 
> annoying this can be.

   FYI, after a few IRC discussions with Markus, we've discovered that 
turning off the memory part of Gnome's System Monitor applet, would get 
rid of the skips. I believe the problem is that both sysctl and the 
sound drivers are Giant-locked, and so there is some contention. An 
easy way to reproduce these skips is to run `while true; do sysctl 
vm.vmtotal; done`, while playing an mp3.

  So, it would be nice to have giant-free sysctl and/or sound drivers.. 

Suleiman Souhlal     | ssouhlal at
The FreeBSD Project  | ssouhlal at

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