Fedora Core 2 wishlists

[Felipe Alfaro Solana]

On Mon, 2003-12-08 at 19:47, Ori Pessach wrote:

> | No, the pre-emptible kernel feature doesn't seem to be quite ready
> | yet.  However, the 2.6 kernel also has the lowlatency patchset applied,
> | and that gives pretty much all of the benefit.  Clark Williams wrote
> | a good paper on this a while ago.
> 
> What are the issues? (a pointer to the Clark Williams paper would be
> fine as an answer). I saw a dramatic improvement in scheduling latency
> when I recompiled the 2.6 test 11 kernel to enable the pre-emptible
> kernel. When compared to the RPM available from
> http://people.redhat.com/arjanv/2.5/RPMS.kernel/, scheduling latency was
> down by an order of magnitude, if I remember correctly. If that kernel
> RPM doesn't contain the lowlatency pathces, that's understandable, but
> otherwise I'm not sure what's going on.

There are some strange, not-easily-reproducible bugs that seems to get
triggered when preemptible is enabled.

> It would be nice not to have to recompile the kernel to get this
> functionality.

Currently, it's impossible to do that, since pre-emption support can't
be enabled as a module. Enabling preemption on-the-fly is not an easy
task so, for the time being, you'll need to recompile.