kernel preemption...

[Ernest L. Williams Jr.]

On Sun, 2004-04-25 at 11:20, Alan Cox wrote:
> On Sat, Apr 24, 2004 at 09:35:46PM -0700, Craig Cruden wrote:
> > I noticed the latest kernels that have been
> > distributed for testing have had the "PREEMPT" flag
> > turned off.  The pre-emption was added for things like
> > sound -- i.e. desktop applications....  when the
> > product is distributed is there going to be a
> > "desktop" kernel version with it turned on by default?
> 
> Pre-empt is vaguely useful for audio but not much else. It also
> slows performance a lot and was primarly merged to help find
> SMP bugs. It only improves typical latency not worst case.
So with respect to kernel development pre-empt is dead for 2.6.X?

> 
> > Also, a side question -- what are the benefits of the
> > "4G/4G" changes (simple explaination) -- right now I
> > am unable to use it turned on on my portable -- so I
> > was wondering what I am missing out on :p
> 
> For slightly lower performance you can run much larger 
> applications. It also happens to help find certain
> classes of kernel bug. The laptop reboot problem should
> have been fixed nowdays btw. You might want to turn it off
> if building for performance.
-- 
Ernest L. Williams Jr. <ernesto at ornl.gov>