Authors: Bartek Wydrowski, Google Research; Robert Kleinberg, Google Research and Cornell; Stephen M. Rumble, Google (YouTube); Aaron Archer, Google ResearchAbstract: We present PReQuaL (Probing to Reduce Queuing and Latency), a load balancer for distributed multi-tenant systems. PReQuaL is designed to minimize real-time request latency in the presence of heterogeneous server capacities and non-uniform, time-varying antagonist load. To achieve this, PReQuaL actively probes server load and levera...