The measured network traffic of compiler-parallelized programs

Using workstations on a LAN as a parallel computer is becoming increasingly common. At the same time, parallelizing compilers are making such systems easier to program. Understanding the traffic of compiler-parallelized programs running on networks is vital for network planning and designing quality of service systems. To provide a basis for such understanding, we measured the traffic of six dense-matrix applications written in a dialect of High Performance Fortran, compiled with the Fx parallelizing compiler, and run on an Ethernet LAN. The traffic of these programs is profoundly different from typical network traffic. In particular the programs exhibit global collective communication patterns, correlated traffic along many connections, constant burst sizes, and periodic burstiness with bandwidth dependent periodicity. The traffic of these programs can be characterized by the power spectra of their instantaneous average bandwidth.