Comparing Web Server Architectures: Events vs Threads

Omkar Gawde and Sameera Padhye

ABSTRACT

This paper tries to answer the age-old question about the performance
of web server architectures - which is better, events vs threads. We
have tried to extensively compare different implementations of web
servers like the multi-process(MP), multi-threaded(MT), event-driven
and hybrid architectures with modern workloads to get a better
perspective of which design better suits modern workloads. This topic
has been greatly debated over the years, however we find that no
recent analysis has been done using modern workloads.  We highlight
the advantages and disadvantages of each approach and come to the
conclusion that neither approach is a one-stop-solution for all
workloads. A hybrid approach is provably better than both individual
approaches. This is because there are a vast variety of tunable
parameters that each offer a different advantage. This then becomes an
applicationspecific design decision. We hope that the results will
help future server architects tune and customize hybrid servers of
their own.