Evaluating the networking characteristics of the Cray XC‐40 Intel Knights Landing‐based Cori supercomputer at NERSC

D Doerfler, B Austin, B Cook, J Deslippe… - Concurrency and …, 2018 - Wiley Online Library
D Doerfler, B Austin, B Cook, J Deslippe, K Kandalla, P Mendygral
Concurrency and Computation: Practice and Experience, 2018Wiley Online Library
There are many potential issues associated with deploying the Intel Xeon PhiTM (code
named Knights Landing [KNL]) manycore processor in a large‐scale supercomputer. One in
particular is the ability to fully utilize the high‐speed communications network, given that the
serial performance of a Xeon PhiTM core is a fraction of a Xeon® core. In this paper, we take
a look at the trade‐offs associated with allocating enough cores to fully utilize the Aries high‐
speed network versus cores dedicated to computation, eg, the trade‐off between MPI and …
Summary
There are many potential issues associated with deploying the Intel Xeon PhiTM (code named Knights Landing [KNL]) manycore processor in a large‐scale supercomputer. One in particular is the ability to fully utilize the high‐speed communications network, given that the serial performance of a Xeon PhiTM core is a fraction of a Xeon®core. In this paper, we take a look at the trade‐offs associated with allocating enough cores to fully utilize the Aries high‐speed network versus cores dedicated to computation, eg, the trade‐off between MPI and OpenMP. In addition, we evaluate new features of Cray MPI in support of KNL, such as internode optimizations. We also evaluate one‐sided programming models such as Unified Parallel C. We quantify the impact of the above trade‐offs and features using a suite of National Energy Research Scientific Computing Center applications.
Wiley Online Library