An Effective Load Balancing Policy for Geometric-Decaying Algorithms

Parallel algorithms are often rst designed as a sequence of rounds where each round includes any number of independent constant time operations This so called work time presentation is then followed by a processor scheduling implementation on a more concrete computational model Many parallel algorithms are geometric decaying in the sense that the sequence of work loads is upper bounded by a decreasing geometric series A standard scheduling implementation of such algorithms consists of a repeated application of load balancing We present a more e ective yet as simple policy for the utilization of load balancing in geometric decaying algorithms By making a more careful choice of when and how often load balancing should be employed and by using a simple amortization argument we show that the number of required applications of load balancing should be nearly constant The policy is not restricted to any particular model of parallel computation and up to a constant factor it is the best possible