PMQS: Scalable linux scheduling for high end servers

Abstract

The Linux kernel scheduler for large SMP and NUMA systems needs to address conflicting requirements of system througput and application response times. This paper presents a pooled multiqueue scheduler (PMQS) de signed for such high-end SMP and NUMA systems. PMQS is based on MQS, a mul tiqueue scheduler that has previously been shown to significantly improve upon the scalability of the current Linux 2.4 scheduler Load imbalances introduced by the pooling approach are reduced by a load balancing module. The paper presents different kinds of load balancers and compares their efficacy. The performance evaluation of PMQS and the load balancer is carried out using application and microbenchmarks with mixed re sults. Pooling is shown to have potential for further improving MQS' performance though more work needs to be done on the load bal ancers.