Better Scalable Algorithms for Broadcast Scheduling

Abstract

In the classical broadcast scheduling problem , there are n pages stored at a server, and requests for these pages arrive over time. Whenever a page is broadcast, it satisfies all outstanding requests for that page. The objective is to minimize average flow time of the requests. For any ϵ > 0, we give a (1+ϵ)-speed O (1/ϵ 3 )-competitive online algorithm for broadcast scheduling. This improves over the recent breakthrough result of Im and Moseley [2010], where they obtained a (1+ϵ)-speed O (1/ϵ 11 )-competitive algorithm. Our algorithm and analysis are considerably simpler than Im and Moseley [2010]. More importantly, our techniques also extend to the general setting of nonuniform page sizes and dependent requests . This is the first scalable algorithm for broadcast scheduling with varying size pages and resolves the main open question from Im and Moseley [2010].