Timo J. Salo

Heuristic-Based Request Scheduling Subject to a Percentile Response Time SLA in a Distributed Cloud

We consider geographically distributed data centers forming a collectively managed cloud computing system hosting multiple applications, each subject to Service Level Agreements (SLA). The Service Level Agreements for each application require the response time of a certain percentile of the input requests to be less than a specified value, with the non-conforming requests being charged a penalty. We present a novel approach of heuristic-based request scheduling at each server, in each of the geographically distributed data centers, to globally minimize the penalty charged to the cloud computing system. We evaluate two variants of our heuristic-based approach, one based on the simulated annealing method of neighborhood searches and another based on gi-FIFO scheduling, which has been analytically proven to be the best schedule for percentile goals in a single machine, multi-class problem. We also compare our approaches with First In First Out (FIFO) and Weighted Round Robin (WRR) scheduling policies.