Abstract
This paper proposes session-aware queue scheduling (SQS), which prevents performance degradation of web application servers under overload. Most of existing admission control are not suitable for real workloads using sessions since they limit the number of concurrent processing either to the whole server or each page. To schedule request processing under real workloads, SQS cooperates page-level schedulers and session-level schedulers. A page scheduler monitors the progress of a web application and detemines an appropriate concurrency level for processing each page. A session scheduler monitors the queue of page requests waiting to be processed in front of each page scheduler and determines the appropriate number of concurrent sessions. We have implemented these schedulers in Tomcat and performed experiments using workloads including sessions. The result shows that SQS improves server throughput for session.
