Impact of Size-Based Scheduling on Web Server Performance

Aditi Deshpande
Paanini Navileka

ABSTRACT

Scheduling policies for requests in Web servers impact the mean
response time, and by extension, the performance of the web server as
a whole. Most server architectures (both event-driven and
thread-based) deal with requests on a strict FCFS (First Come, First
Serve) basis, an approach that is fair to all requests, regardless of
the size of the payload. By doing away with the notion of fairness
in web servers, we open ourselves to other scheduling algorithms, that
may yield drastic improvements in performance un- der specific
workloads. In this paper, we have explored the effects of using the
Shortest Remaining Processing Time (SRPT) scheduling algorithm as a
replacement for the traditional FCFS. Our results show that in
workloads where the size of the request in known beforehand,
prioritizing smaller requests over larger ones can yield significant
improvements in mean response time for access patterns where smaller
files are more frequently requested than larger files.