O'Reilly Open Source Software Convention 2002

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From the Frontiers of Research to the Heart of the Enterprise
O'Reilly Open Source Convention
Sheraton San Diego Hotel and Marina
July 22-26, 2002 -- San Diego, CA

Apache
Tutorial
Optimize Your Perl Code
Robert Spier, Google

Track: Perl
Date: Tuesday, July 23
Time: 8:45am - 12:15pm
Location: Grande Ballroom B
This tutorial is an introduction to optimizating perl applications. It's important knowledge for anyone writing time-sensitive applications, from a CGI script to a large application.
It covers the following four major components:

A brief introduction to complexity theory
Just enough complexity theory to have a basic language to talk about runtimes of functions. O(1), O(n), O(n^2), etc. Complexity of common perl idioms like map, sort, nested loops, etc. Why is some code slow? (And it's not perl's fault!)

Real world / real code examples and how to make them faster
Examples of O(n^2) or worse functions and how they can be improved by an order of magnitude by rewriting the algorithm, and possibly changing the data structures used to store things. Memoization/Caching/Persistency/Precomputing.

Some simple Benchmarking
Devel::DProf and Benchmark.pm can help to isolate problem spots in your code. Learn how to properly interpret data and how to pick the "important" pieces.

Is it worth it?
Not all time spent optimizing the code is worth it. There are tradeoffs of time, readability, speed. Discuss development strategies, pre-optimization, and over-optimization. O(n) can be faster than O(1) for small n.