  In this paper we investigate performance of global communications in a
particular parallel code. The code simulates dynamics of expansion of premixed
spherical flames using an asymptotic model of Sivashinsky type and a spectral
numerical algorithm. As a result, the code heavily relies on global all-to-all
interprocessor communications implementing transposition of the distributed
data array in which numerical solution to the problem is stored. This global
data interdependence makes interprocessor connectivity of the HPC system as
important as the floating-point power of the processors of which the system is
built. Our experiments show that efficient numerical simulation of this
particular model, with global data interdependence, on modern HPC systems is
possible. Prospects of performance of more sophisticated models of flame
dynamics are analysed as well.
