QPACE 2 and Domain Decomposition on the Intel Xeon Phi∗ Paul Artsa, Jacques Blochb, Peter Georgb, Benjamin Glässleb, Simon Heybrockb, Yu Komatsubarac, Robert Lohmayerb, Simon Magesb, Bernhard Mendlb, Nils Meyerb, Alessio Parcianelloa, Dirk Pleiterb;d, Florian Rapplb, Mauro Rossia, Stefan Solbrigb, Giampietro Tecchiollia, Tilo Wettig†b, Gianpaolo Zaniera aEurotech HPC, Via F. Solari 3/A, 33020 Amaro, Italy bDepartment of Physics, University of Regensburg, 93040 Regensburg, Germany cAdvanet Inc., 616-4 Tanaka, Kita-ku, Okayama 700-0951, Japan dJSC, Jülich Research Centre, 52425 Jülich, Germany E-mail:
[email protected] We give an overview of QPACE 2, which is a custom-designed supercomputer based on Intel Xeon Phi processors, developed in a collaboration of Regensburg University and Eurotech. We give some general recommendations for how to write high-performance code for the Xeon Phi and then discuss our implementation of a domain-decomposition-based solver and present a number of benchmarks. arXiv:1502.04025v1 [cs.DC] 13 Feb 2015 The 32nd International Symposium on Lattice Field Theory, 23-28 June, 2014 Columbia University, New York, NY ∗Work supported by DFG in the framework of SFB/TRR-55. †Speaker. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it/ QPACE 2 and Domain Decomposition on the Intel Xeon Phi Tilo Wettig 1. Introduction After the invention of lattice QCD in 1974 [1] it quickly became clear that (i) it had great potential to yield physically relevant nonperturbative results and (ii) enormous computational re- sources would be required to obtain them.