Coflow scheduling in input-queued switches: Optimal delay scaling and algorithms
Author(s)Liang, Qingkai; Modiano, Eytan H
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A coflow is a collection of parallel flows belonging to the same job. It has the all-or-nothing property: a coflow is not complete until the completion of all its constituent flows. In this paper, we focus on optimizing coflow-level delay, i.e., the time to complete all the flows in a coflow, in the context of an N × N input-queued switch. In particular, we develop a throughput-optimal scheduling policy that achieves the best scaling of coflow-level delay as N → ∞. We first derive lower bounds on the coflow-level delay that can be achieved by any scheduling policy. It is observed that these lower bounds critically depend on the variability of flow sizes. Then we analyze the coflow-level performance of some existing coflow-agnostic scheduling policies and show that none of them achieves provably optimal performance with respect to coflow-level delay. Finally, we propose the Coflow-Aware Batching (CAB) policy which achieves the optimal scaling of coflow-level delay under some mild assumptions.
DepartmentMassachusetts Institute of Technology. Department of Aeronautics and Astronautics; Massachusetts Institute of Technology. Laboratory for Information and Decision Systems
IEEE INFOCOM 2017 - IEEE Conference on Computer Communications
Institute of Electrical and Electronics Engineers (IEEE)
Liang, Qingkai, and Eytan Modiano. “Coflow Scheduling in Input-Queued Switches: Optimal Delay Scaling and Algorithms.” IEEE INFOCOM 2017 - IEEE Conference on Computer Communications (May 2017).