Providing Differentiated Levels of Service in Web Content Hosting
Jussara Almeida, Mihaela Dabu, Anand Manikutty and Pei Cao
Computer Sciences Department
University of Wisconsin-Madison
Currently the paper can be referenced as "Technical Report, Computer Sciences Department, University of Wisconsin-Madison."
Here is the paper in compressed postscript.
Web content hosting, in which a Web server stores and provides Web access
to documents for different customers, is becoming increasingly common.
Due to the variety of customers (corporate, individuals, etc.), providing
differentiated levels of service is often an important issue for the hosts.
Most server implementations, however, are not structured to service
requests based on different levels of quality of service (QoS). This paper
presents our attempts at augmenting a popular server implementation
with differentiated QoS features.
We explore priority-based request scheduling at both user and kernel levels.
We find that simple strategies such as controlling the numbers of
processes can improve the response time of high-priority requests notably
while preserving the system throughput. We also find that the kernel-level
approach tends to penalize low-priority requests less significantly than
the user-level approach, while improving the performance of high-priority
requests similarly. Based on our experiments, we discuss the bottlenecks
and limitations from kernel implementations that prevent the augmented
server from achieving better performance.