[_wmd]

I think the keyword here is transparency -- later designs (even stuff like MPI) explicitly expose the topology of the available hardware. SMP is the closest thing we've ever got to true transparency, and then only for 80% of cases, and for those only because the compute nodes have very similar locality and e.g. memory bandwidth

Even SMP requires careful control if you want to get anything close to the actual performance of the underlying hardware, and the topology is once again very explicit

[gnufx]

You better specify what "SMP" means. By definition, Symmetric Multi-Processing doesn't have locality concerns, but that's basically dead, and Shared Memory Programming does, indeed, typically require attention to topology and thread binding -- frequently ignored, of course. I don't know the MPI standard well, but I didn't think there was anything requiring topology to be exposed, and it won't be in the absence of something like netloc, which is still experimental.