why did Ubuntu turn off kernel preemption in Edgy?

Ben Collins ben.collins at ubuntu.com
Mon Nov 27 02:15:10 GMT 2006

On Mon, 2006-11-27 at 00:24 +0000, Toby Smithe wrote:
> On Sun, 2006-11-26 at 19:11 -0500, Ben Collins wrote:
> > On Sun, 2006-11-26 at 09:41 -0800, Adam Dingle wrote:
> > > In the Edgy kernel we've turned off CONFIG_PREEMPT, turning on 
> > > CONFIG_PREEMPT_VOLUNTARY instead (see the changelog excerpt below).  
> > > This change may not be great for multimedia users (especially those 
> > > editing audio) since it can increase latency.  Out of curiosity, what 
> > > was the motivation for this?
> > 
> > Because a lot of laptops didn't like this setup. It caused an increase
> > in timer related interrupts, which resulted in a significant decrease in
> > batter life.
> > 
> > For feisty, I'm considering a low latency targeted kernel for audio
> > users. However, I'm a little reluctant, mainly because I never hear from
> > any of the multimedia users (like you) who are interested in this sort
> > of functionality until after we release, which for me means I wont get
> > any testing on these kernels until after it's too late to fix things.
> I think we would be more able to test a kernel if it was available ;)
> Everyone at Ubuntu Studio would love this, and you can take that as a
> given. If we get a kernel ready for testing, we will test it!

That didn't seem to be the case for edgy, considering no one mentioned
it until after release :)

More information about the ubuntu-devel mailing list