[linux-audio-dev] Linux 2.6 not a latency panacea?

[Christian Henz]

On Wed, Aug 13, 2003 at 03:09:10PM -0700, Joshua Haberman wrote:
> I am distressed.  It was my understanding that the 2.5/2.6 kernel branch 
> was undergoing significant scheduler and latency work, and that 2.6 
> would eliminate the kernel from the list of obstacles of low-latency on 
> Linux.  It will have the preemptable kernel patch, the new scheduler, 
> and all of Ingo Molnar's low-latency work.  Claims were being thrown 
> around that 2.6 would be the lowest-latency operating system on the planet.
> 
> So how is it that we're in the 2.6.0-test series and people are 
> complaining about audio skipping in **XMMS**, which uses three second 
> buffers by default??  If people are getting skips from high-latency 
> playback, what hope is there for low-latency audio?  A series of patches 
> are coming from both Ingo and Con Kolivas attempting to address this, 
> but the fact they are just now throwing around potential solutions 
> erodes at my faith that they really understand the problem or how to 
> solve it.
> 
> Is 2.6.x going to be suitable for low-latency (or even reliable 
> high-latency) audio?  Or is it going to be more of the same: patching 
> the kernel, tweaking parameters, reading magical incantations, and 
> hoping for the best?
> 
> Reassure me please!
> 
> Josh
> 

I also found 2.6.0-test[123] to be less responsive than 2.4.x-ll, or even stock 2.4.x. I've also experienced XMMS dropouts under load (for example compiling Muse)

Some behaviour I've noticed is that under heavy load the desktop/audio doesn't freeze for a certain block of time, but rather in short (~2 seconds) intervalls...

cheers,
Christian Henz