why did Ubuntu turn off kernel preemption in Edgy?

Ben Collins ben.collins at ubuntu.com
Mon Nov 27 00:11:48 GMT 2006

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.

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