Dodoor: Efficient Randomized Decentralized Scheduling with Load Caching for Heterogeneous Tasks and Clusters
Wei Da, Evangelia Kalyvianaki
TL;DR
Dodoor tackles efficient task scheduling in heterogeneous data centers by replacing per-request probing with batched, centrally pushed load caches. It introduces a novel anti-affinity resource-load score (RL) and uses a two-choice selection to place tasks, balancing resource demands and execution durations. Empirical results on a 101-node cluster show up to 55–66% reduction in scheduling messages, up to 33.2% throughput gains, and notable improvements in mean and tail makespan across Azure VM traces and serverless FunctionBench workloads. The design emphasizes resilience and scalability through asynchronous updates and a push-based data store, offering practical benefits for real-world cloud environments.
Abstract
This paper introduces Dodoor, an efficient randomized decentralized scheduler designed for task scheduling in modern data centers. Dodoor leverages advanced research on the weighted balls-into-bins model with b-batched setting. Unlike other decentralized schedulers that rely on real-time probing of remote servers, Dodoor makes scheduling decisions based on cached server information, which is updated in batches, to reduce communication overheads. To schedule tasks with dynamic, multidimensional resource requirements in heterogeneous cluster, Dodoor uses a novel load score to measure servers' loads for each scheduled task. This score captures the anti-affinity between servers and tasks in contrast to the commonly used heuristic of counting pending tasks to balance load. On a 101-node heterogeneous cluster, Dodoor is evaluated using two workloads: (i) simulated Azure virtual machines placements and (ii) real serverless Python functions executions in Docker. The evaluation shows that Dodoor reduces scheduling messages by 55--66% on both workloads. Dodoor can also increase throughput by up to 33.2% and 21.5%, reduce mean makespan latency by 12.1% and 7.2%, and improve tail latency by 21.9% and 24.6% across the two workloads.
