NAME

Net::Analysis::Listener::HTTPClientPerf - analysis of client performance

SYNOPSIS

Listens for: tcp_packet tcp_session_start tcp_session_end http_transaction

No events are emitted.

ABSTRACT

Generate a pretty PostScript file with HTTP sessions, requests and packets shown along a time axis. It is geared towards TCP sessions arising over a short time span (say, <40s) originating from a single browser.

CONFIGURATION

 v                - verbosity
 tsnap=NN         - the width of each packet column, in microseonds. Larger
                     values compress the graph; packet columns become taller.
                     Defaults to 25000ms.
 show_all_packets - plot non-data packets as well as data packets
 file             - output filename
 pdf              - whether to exec `gs -sDEVICE=pdfwrite -sOUTPUTFILE=out.pdf`
 ggv              - whether to auto-invoke ggv on the output

DESCRIPTION

We listen to the http_transaction events, and build up a data structure designed for a graphical report.

Each time we see tcp_sesssion_start, we start up a new session box. In this box, we build a packet histogram over time, as tcp_packet events are seen. The tsnap setting defines the time window; any packets for that session that flow within the window are added together. At the end, each window will contain a count of the packets, and also counts for the different classes (data vs. duplicates vs. non-data, etc).

As we see http_transaction events, we classify them based on their headers. A record of the times, and class, of each transaction is added to the session box.

When the session box is closed, we run through the various histograms, and assign each set of counters a HTTP classification based on which http transaction event their time lies within (e.g. request, response). We then run through the http transaction list and insert req_start,req_stop, resp_start, and resp_stop timings into the histogram sequence.

At this point, for each session we now have a time-ordered sequence of http event timings, and fully classified packet histograms.

We now do a quick check over all the session boxes, to get scales for the axes. Horiztonal is time; vertical is number of packets. We draw the axes, and also any relevant graph furniture.

Then draw all the boxes. Sessions are stacked where they are concurrent; else they are fitted in, to give a sense of the number of concurrent sessions that were used during the request.

TODO

Better autoscaling of time axis; tsnap should be fully automatic

Output SVG instead of PostScript.

Incorporate DNS lookups.

Classify HTTP transactions; say, javascript vs. adserver vs. content vs. images

SEE ALSO

Net::Analysis - the framework this module sits on.

AUTHOR

Adam B. Worrall, <worrall@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2004 by Adam B. Worrall

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.5 or, at your option, any later version of Perl 5 you may have available.