We describe our experience porting the Regensburg implementation of the
DD-αAMG solver from QPACE 2 to QPACE 3. We first review how the code was
ported from the first generation Intel Xeon Phi processor (Knights Corner) to
its successor (Knights Landing). We then describe the modifications in the
communication library necessitated by the switch from InfiniBand to Omni-Path.
Finally, we present the performance of the code on a single processor as well
as the scaling on many nodes, where in both cases the speedup factor is close
to the theoretical expectations.Comment: 12 pages, 6 figures, Proceedings of Lattice 201
