We default to ch3:sock. Scott MacLachlan just had a long thread on the Firedrake list where it ended up that reconfiguring using ch3:nemesis had a 2x performance boost on his 16-core proc, and noticeable effect on the 4 core speedup. Why do we default to sock? Thanks, Matt -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>