Scheduling Coflows in Datacenter Networks: Improved Bound for Total Weighted Completion Time

Coflow is a recently proposed networking abstraction to capture communication patterns in data-parallel computing frameworks. We consider the problem of efficiently scheduling coflows with release dates in a shared datacenter network so as to minimize the total weighted completion time of coflows. Specifically, we propose a randomized algorithm with approximation ratio of 3e ~ 8.155, which improves the prior best known ratio of 9+16 √2/3 ~ 16.542. For the special case when all coflows are released at time zero, we obtain a randomized algorithm with approximation ratio of 2e ~ 5.436 which improves the prior best known ratio of 3+2√2 ~ 5.828$. Simulation result using a real traffic trace is presented that shows improvement over the prior approaches.