SCHED_4BSD in RELENG_7 disturbs workflow

I know that RELENG_7 is not considered very near-release, but I thought I'd
give my 2¢ in the hope that I might have a little influence on the scheduler
development to my benefit.

The switch from RELENG_6 to RELENG_7 went relatively smooth and apart from ipw
causing panics. However there is one thing that's disturbing and this is the
scheduler. I only have single core machines, so whatever I say only applies to
those. If you think single-core machines are no longer important, feel free to
ignore this. In deed, just ignore me however much you like.

>From my perspective scheduling on RELENG_6 was way better. Even on a full
workload like a portupgrade the focused application (both in X and on the
console) always received enough cycles to run smoothly and applications that
ran in background like audio players also kept on running fine.

Quite the contrary on RELENG_7. During a portupgrade or even worse 'pkgdb -L'
(recovering lost dependencies) audio players (both graphical and mplayer)
scatter, either because they don't get the hard-disk or CPU-cycles (which one,
I don't know) and the focused application also often hangs. It just looks like
occasionally (under load) everything freezes for a second and then goes on
relatively normal.

I've got the impression that things compile a little faster (that might be my
imagination, though), but I'd rather have a smooth working experience.

This is just my view of the situation and I suppose it is only one of many. I
bid you be merciful with us single-core people, who cannot afford a slick
multi-core machine, because we worry how to pay for our food at the end of the
month.