In a new whitepaper, Andrey Vladimirov of Stanford University and Vadim Karpusenko of Colfax International investigates the porting and optimization of an N-body test problem for the Intel Xeon Phi coprocessor.
The test problem is a basic N-body simulation, which is the foundation of a number of applications in computational astrophysics and biophysics. Using common code in the C language for the host processor and for the coprocessor, they benchmark the N-body simulation. The simulation runs 2.3x to 5.4x times faster on a single Intel Xeon Phi coprocessor than on two Intel Xeon E5 series processors. The performance depends on the accuracy settings for transcendental arithmetics. They also study the assembly code produced by the compiler from the C code. This allows to pinpoint some strategies for designing C/C++ programs that result in efficient automatically vectorized applications for Intel Xeon family devices.