I have a reproducible slowing down of calculations due to something which is going to be hard to track down so I welcome suggestions. I do not know if this is a memory leak, impi related, mkl related or what.
I first noticed it when one newish E5-2660 node was systematically running at ~1/2 the speed of others for mpi calculations, reproducibly. After rebooting it went back to running at the same speed as others, nothing else helped.
