Efficient C++ Performance Programming Techniques

80-20 Rule: Speed Up the Common Path

The 80-20 rule has many applications: 80% of the execution scenarios will traverse only 20% of your source code, and 80% of the elapsed time will be spent in 20% of the functions encountered on the execution path. The 80-20 rule is the dominating force driving the argument that premature tuning is a sin. If you randomly tune everything you can think of, not only do you waste 80% of the effort, you will also hack the design beyond repair.

The HTTP specification is a 100-page document that describes all possible HTTP requests that a Web server must handle. Most of the HTTP requests that traverse the Web these days are very simple. They contain only a small subset of the possible HTTP headers that a request could ...