TY - CONF A1 - Zhao, Zhengji A1 - Marsman, Martijn A1 - Wende, Florian A1 - Kim, Jeongnim T1 - Performance of Hybrid MPI/OpenMP VASP on Cray XC40 Based on Intel Knights Landing Many Integrated Core Architecture N2 - With the recent installation of Cori, a Cray XC40 system with Intel Xeon Phi Knights Landing (KNL) many integrated core (MIC) architecture, NERSC is transitioning from the multi-core to the more energy-efficient many-core era. The developers of VASP, a widely used materials science code, have adopted MPI/OpenMP parallelism to better exploit the increased on-node parallelism, wider vector units, and the high bandwidth on-package memory (MCDRAM) of KNL. To achieve optimal performance, KNL specifics relevant for the build, boot and run time setup must be explored. In this paper, we present the performance analysis of representative VASP workloads on Cori, focusing on the effects of the compilers, libraries, and boot/run time options such as the NUMA/MCDRAM modes, Hyper-Threading, huge pages, core specialization, and thread scaling. The paper is intended to serve as a KNL performance guide for VASP users, but it will also benefit other KNL users. Y1 - 2017 UR - https://opus4.kobv.de/opus4-zib/frontdoor/index/index/docId/6510 N1 - Availability: https://cug.org/conference-proceedings ER -