pkgsrc bulk build profile

[Justin C. Sherrill]

Something interesting I noticed while doing an initial bulk pkgsrc build
on df.v12.su:

Build start: 2009-02-13 04:26
Build end:   2009-02-20 18:46

This machine has 4 2.4G cpus, but I think this is the same time I'd get on
single-CPU pkgbox under good circumstances.  My handwaving guess is that
either the pbulk process combined with the BGL is I/O bound, not CPU
bound.

I recall Joerg had mentioned using VMWare to put multiple hosts on a
single machine, and then using pbulk's internal distributed build method
to spread work between those hosts; that may be possible on this system
if/when Qemu works on DragonFly?

Other ideas welcome; I'd like to use bulk pkgsrc builds as a sort of
performance profile, plus anything that makes them faster is good.