Re: kernel preemption...

[Alan Cox <alan redhat com>]

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.

> 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.