In this paper, we extensively tune and then compare the performance of web servers based on three different server architectures. The µserver utilizes an event-driven architecture, Knot uses the highly-efficient Capriccio thread library to implement a thread-perconnection model, and WatPipe uses a hybrid of events and threads to implement a pipeline-based server that is similar in spirit to a staged event-driven architecture (SEDA) server like Haboob. We describe modifications made to the Capriccio thread library to use Linux’s zero-copy sendfile interface. We then introduce the SYmmetric Multi-Processor Event Driven (SYMPED) architecture in which relatively minor modifications are made to a single process event-driven (SPED) server (the µserver) to allow it to continue processing requests in the presence of blocking due to disk accesses. Finally, we describe our C++ implementation of WatPipe, which although utilizing a pipeline-based architecture, excludes the dynamic control...
David Pariag, Tim Brecht, Ashif S. Harji, Peter A.