ULE patch, call for testers

[Jeff Roberson]

I have a small patch to the ULE scheduler that makes a fairly large change 
to the way timeshare threads are handled.

http://people.freebsd.org/~jeff/schedslice.diff

Previously ULE used a fixed slice size for all timeshare threads.  Now it 
scales the slice size down based on load.  This should reduce latency for 
timeshare threads as load increases.  It is important to note that this 
does not impact interactive threads.  But when a thread transitions to 
interactive from timeshare it should see some improvement.  This happens 
when something like Xorg chews up a lot of CPU.

If anyone has perf tests they'd like to run please report back.  I have 
done a handful of validation.

Thanks,
Jeff