How to Make Things Faster

Chapter 30. Event Count

There are only two ways to improve the response time of a computer program: (1) reduce a profile component’s event count or (2) reduce a profile component’s mean duration per event. In this chapter, I will tell you about the first way: reducing event counts.

In the tomato story I told earlier, eliminating the chocolate bars saved $40.00 of a $55.48 grocery bill:

You’ll see the same kinds of opportunities in the receipt-style profile of a computer program. Opportunities to reduce event counts can occur anywhere from Nancy’s brain all the way down to your computer’s silicon. That’s because everyone who has ever played a part in designing, building, configuring, managing, or using your system has had countless opportunities to accidentally add waste to your system. Our job is to recognize the waste that matters and get rid of it.

So, programs execute lots of events. How can you tell the wasteful ones from the necessary ones? Sometimes it’s as easy as the chocolate bar question. If you don’t need a feature, then turn it off! Others, you just have to learn. You’ll learn from blogs and papers and conferences, and books and courses and your own experiences, and friends and colleagues and vendors, and from tests you do yourself.

You can fast-track your progress by tracing important application tasks when they’re running at speeds that everyone is satisfied with. ...