Re: [gentoo-ppc-user] Kernel Preemption

[Erik Zeek]

On Wed August 3 2005 08:15 am, Mike S wrote:
> <snipped from another thread>
>
> On Mon August 1 2005 07:26 am, Mike S wrote:
> >> > Is kernel preemption a bad thing?
> >> >
> >> > --Mike S
> > >
> > > No, just broken.
> >
> > Unless you enable SMP in conjunction with it (yes, even if you _only have
> > one CPU_!).
>
> I opted to use an upstream kernel.  Is this also broken here, or just in
> the gentoo kernel?  And I do have SMP enabled.  Basically whatever
> speed-ups I can get I am trying to use.
>
> --Mike S

As I understand, it preemption is not exactly a speedup.  It is supposed to 
improve the responsiveness of the kernel to user input.  The kernel can 
switch contexts in more places inside the kernel in response to other inputs.  
This is great for desktops, but probably not for servers/number crunchers.

I have no idea if it's fixed or not.  Try disabling SMP and enabling 
preemption followed by an emerge of something large (openoffice, kde, you 
pick).  If it succeeds, maybe it's fixed.  If not, then it's still broken.

Erik

P.S.  I'm no expert on the kernel (I'm a laser physicist.), so you might be 
better off Googling for an answer.
-- 
*******************************************
Dr. Erik Zeek
Postdoctoral Research Associate
Department of Physics and Astronomy
The University of Georgia
Athens, GA 30602-2451

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