System Performance Tuning, 2nd Edition

Chapter 1. An Introduction to Performance Tuning

There are a thousand hacking at the branches of evil to one who is striking at the root.

—Henry David Thoreau, 1854

Going faster seems to be a central part of human development. As little as three hundred years ago, the fastest you could expect to go was a few tens of miles an hour, aboard a fast clipper ship with a stiff wind behind you. Now, we must expand our view to things such as the fastest achievable speed while remaining in the Earth’s atmosphere -- perhaps fifteen hundred miles an hour, twice the speed of sound, if you are a civilian without access to the latest, fastest military aircraft. The journey that used to take three weeks under sail from London to New York City now takes us as little as two and a half hours, sipping champagne the whole way.

This innate human desire to go fast is expressed in many ways: microwave ovens let us cook dinner quickly, high-performance automobiles and motorcycles give us a wonderful thrill, email lets us communicate at almost the speed of thought. But what happens when that email server is overwhelmed, as when we all log in at eight o’clock in the morning to check what has gone on while we’ve slept? Or when the procurement system for the company that distributes microwave ovens is only able to handle half of the workload, or when a mechanical engineer’s CAD system runs so slowly that the car engine she’s designing won’t be ready in time for the new model year?

These are the problems facing ...