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Inferring client response time at the web server
Written by:
David Olshefski,
Jason Nieh, and
Dakshi Agrawal.
Citation:
Proceedings of the 2002 ACM SIGMETRICS international conference on Measurement and modeling of computer systems, pages 160-171. ACM Press, 2002.
Copyright © (2002) by Association for Computing Machinery,
Inc. Permission to make digital or hard copies of part of all of this
work for personal or classroom use is granted without fee provided that
copies are not made or distributed for profit or commercial advantage. To
copy otherwise, to republish, to post on servers, or to redistribute to
lists, requires prior specific permission and/or a fee.
Abstract:
As businesses continue to grow their World Wide Web presence, it is
becoming increasingly vital for them to have quantitative measures of the
client perceived response times of their web services. We present Certes
(CliEnt Response Time Estimated by the Server), an online server-based
mechanism for web servers to measure client perceived response time,
as if measured at the client. Certes is based on a model of TCP that
quantifies the effect that connection drops have on perceived client
response time, by using three simple server-side measurements: connection
drop rate, connection accept rate and connection completion rate. The
mechanism does not require modifications to http servers or web pages,
does not rely on probing or third party sampling, and does not require
client-side modifications or scripting. Certes can be used to measure
response times for any web content, not just HTML. We have implemented
Certes and compared its response time measurements with those obtained
with detailed client instrumentation. Our results demonstrate that
Certes provides accurate server-based measurements of client response
times in HTTP 1.0/1.1 [14] environments, even with rapidly changing
workloads. Certes runs online in constant time with very low overhead. It
can be used at web sites and server farms to verify compliance with
service level objectives.
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