Java Performance Tuning

A Tuning Strategy

Here’s a strategy I have found works well when attacking performance problems:

1. Identify the main bottlenecks (look for about the top five bottlenecks, but go higher or lower if you prefer).

2. Choose the quickest and easiest one to fix, and address it (except for distributed applications where the top bottleneck is usually the one to attack: see the following paragraph).

3. Repeat from Step 1.

This procedure will get your application tuned the quickest. The advantage of choosing the “quickest to fix” of the top few bottlenecks rather than the absolute topmost problem is that once a bottleneck has been eliminated, the characteristics of the application change, and the topmost bottleneck may not even need to be addressed any longer. However, in distributed applications I advise you target the topmost bottleneck. The characteristics of distributed applications are such that the main bottleneck is almost always the best to fix and, once fixed, the next main bottleneck is usually in a completely different component of the system.

Although this strategy is simple and actually quite obvious, I nevertheless find that I have to repeat it again and again: once programmers get the bit between their teeth, they just love to apply themselves to the interesting parts of the problems. After all, who wants to unroll loop after boring loop when there’s a nice juicy caching technique you’re eager to apply?

You should always treat the actual identification of the cause of the performance bottleneck ...