Scheduler patch 02 available for testing

[Matthew Dillon]

    I've been working on the scheduler issues for the last two days.

	http://leaf.dragonflybsd.org/~dillon/sched02.patch

    The work is intended to solve jerkiness / other scheduler issues related
    to mixed batch / interactive loads.  I fixed a number of low level issues
    that were causing the scheduler to make bad choices in regards to what
    to schedule, even in the face of properly working statistical measurements.
    I also added a long-term interactivity measurement which so far appears
    to do a good job discerning between, say, a buildworld and X/mozilla.

    I'm not so sure how will it will do with, e.g. audio and video playback...
    probably not so well with video in the face of other batch ops.  It does
    degrade pipe throughput slightly (mainly because the hacks I had
    added to the existing scheduler to make pipe throughput better screwed
    up other things so I backed them out in this patch).

    In anycase, I'm looking for people to test the stability and value of
    the changes verses what we had before, especially on MP systems.  It
    is entirely untested on MP systems.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>