Abstract
If cluster C 1 consists of computers with a faster mean speed than the computers in cluster C 2 , does this imply that cluster C 1 is more productive than cluster C 2 ? What if the computers in cluster C 1 have the same mean speed as the computers in cluster C 2 : is the one with computers that have a higher variance in speed more productive? Simulation experiments are performed to explore the above questions within a formal framework for measuring the performance of a cluster. Simulation results show that both mean speed and variance in speed (when mean speeds are equal) are typically correlated with the performance of a cluster, but not always; these statements are quantified statistically for our simulation environments. In addition, simulation results also show that: (1) If the mean speed of computers in cluster C 1 is faster by at least a threshold amount than the mean speed of computers in cluster C 2 , then C 1 is more productive than C 2 . (2) If the computers in clusters C 1 and C 2 have the same mean speed, then C 1 is more productive than C 2 when the variance in speed of computers in cluster C 1 is higher by at least a threshold amount than the variance in speed of computers in cluster C 2 .