Macrotasking and microtasking a Navier-Stokes algorithm on the Cray-2
R. Fatoohi · 1989
This paper presents the results of macrotasking and microtasking a Navier-Stokes algorithm on the Cray-2. The algorithm is a compact difference scheme for the solution of the incompressible, two-dimensional, time dependent Navier-Stokes equations. Two implementations of multitasking on the Cray-2 are considered. These are: macrotasking (parallelism at the subroutine level) and microtasking (parallelism at the do-loop level). These two techniques are briefly described. The implementation of the algorithm is discussed in relation to these techniques and the results for three problem sizes are presented. The timing results for both techniques are in general comparable with differences ranging between 2% to 14% depending on the problem size. The best achieved speedup in a dedicated environment is 3.62 for macrotasking and 3.32 for microtasking. Finally, comparisons are made and conclusions are drawn.