An Adaptive Scheduling Policy for Staged Applications

The performance of Web servers and application servers is a crucial factor for the success of the underlying business activity. Current commercial servers (such as Apache and Microsoft’s IIS) usually employ a thread-based concurrency policy for executing request simultaneously. However, with this policy the throughput tends to collapse when massive overload occurs. Event-based concurrency has been proposed as an alternative, but –similar to the thread-based approach– it suffers in its pure form from a potential memory access bottleneck. This is avoided by a server based on a Staged Event-Driven Architecture (SEDA) which combines the two approaches to take advantage of locality in data and code within each state. In this paper, we present a three layer observer/controller architecture for dynamic performance control of SEDA-based application servers. Control is achieved by a strategy which adapts the resources assigned to each stage based on the observed throughput and queue leng...

• Type: Conference
• Year: 2009
• Where: ICIW
• Authors: Mohammad Shadi Al Hakeem, Jan Richling, Gero Mühl, Hans-Ulrich Heiss
• Keywords: Application Servers, Current Commercial Servers, ICIW 2009, Internet Technology, Thread-based Concurrency Policy