Performance of PVM with the MOSIX preemptive process migration scheme

With the increased interest in workstation networks for parallel and high performance computing it is necessary to reexamine the use of process migration algorithms, to improve the overall utilization of the system, to achieve high performance and to allow flexible use of idle workstations. Currently, almost all programming environments for parallel systems do not use process migration for task assignments. Instead, a static process assignment is used, with sub-optimal performance, especially when several users execute multiple processes simultaneously. The paper highlights the advantages of a process migration scheme for better utilization of the computing resources as well as to gain substantial speedups in the execution of parallel and multi-tasking applications. The authors executed several CPU and communication bound benchmarks under PVM, a popular programming environment for parallel computing that uses static process assignment. These benchmarks were executed under the MOSIX multicomputer operating system, with and without its preemptive process migration scheme. The results of these benchmarks prove the advantages of using preemptive process migrations. The paper begins with an overview of MOSIX, a multicomputer enhancement of UNIX that supports transparent process migration for load-balancing, and PVM. They then present the performance of the executions of the benchmarks. Their results show that in some cases the improvements in the performance of PVM with the MOSIX process migration can reach tens or even hundreds of percents.