Towards Hybrid Cooperative-Preemptive Scheduling
Yizheng Xie, Di Jin, Nikos Vasilakis · 2025
Cooperative scheduling avoids the many shared-state pitfalls of preemption, but risks fairness---in the limit resulting in denial of service and resource exhaustion. This paper argues that a careful hybrid between cooperation and preemption is both feasible and advantageous: by allowing only carefully controlled and developer-configurable preemption in an otherwise cooperative environment, the scheduler can maintain key invariants while restoring fairness. The paper presents a series of case-study workloads that motivate the need for preemption in real-world cooperative environments, sketches a hybrid design that introduces controlled preemption while maintaining cooperation benefits, and discusses the benefits by applying this hybrid design on the case-study workloads. A hybrid scheduling implementation, Cx, is in progress.