It would appear, after a very short scan of the doc, that both Linux and BSD have modified the schedulers with the specific goal of clustering in mind. It looks like Linux does pretty good overall from the charts, but there are certain areas that need improvement and the new BSD w/ ULE looks pretty good. I wonder what would happen if one of the top 5 supercomputers were to load BSD. I bet the SGI machine could run BSD, doubt there is a BSD for BlueGene though.