The smart is more slower if you use more package as the arguements, for example: If A requires B -> C -> D: "smart install A" is much faster than "smart install A B C D", though, the results are the same (all of A B C D will be installed), this makes oe-core install COMPLEMENTARY very slow since the COMPLEMENTARY is usually a long list.
Merged into master: http://git.openembedded.org/openembedded-core/commit/?id=dae4149009be722943cc7deec7f03e87b77ea59b