why did Ubuntu turn off kernel preemption in Edgy?

Toby Smithe toby.smithe at gmail.com
Mon Nov 27 00:24:10 GMT 2006

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!

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