The Measured Network Traffic of Compiler–Parallelized Programs Peter A. Dinda Brad M. Garcia Kwok-Shing Leung July 1998 CMU-CS-98-144 School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Abstract Using workstations interconnected by a LAN as a distributed parallel computer is becoming in- creasingly 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 for designing quality of service interfaces and mechanisms for new networks. To provide a basis for such understanding, we measured the traffic of six dense-matrix applications written in a dialect of High Performance Fortran and compiled with the Fx paralleliz- ing compiler. 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 period- icity. The traffic of these programs can be characterized by the power spectra of their instantaneous average bandwidth. These spectra can be simplified to form analytic models to generate similar traffic.