The effect of heavy-tailed distribution on the performance of non-contiguous allocation strategies in 2D mesh connected multicomputers

The performance of non-contiguous allocation strategies has been evaluated under the assumption that the number of messages sent by jobs, which is one of the factors that the job execution times depend on, follow an exponential distribution. However, many measurement studies have convincingly demonstrated that the execution times of certain computational applications are best characterized by heave-tailed, job execution times. In this paper, the performance of existing non-contiguous allocation strategies is revisited in the context of heavy-tailed distributions. The strategies are evaluated and compared using simulation experiments for both First-Come-First-Served (FCFS) and Shortest-Service-Demand (SSD) scheduling under a variety of system loads and system sizes. The results show that the performance of the non-contiguous allocation strategies degrades considerably when the number of messages sent follow a heavy-tailed distribution against that of the exponential distribution. Moreover, SSD copes much better than FCFS scheduling in the presence of heavy-tailed job execution times.