Locating the bottleneck

WEBINAR: On-demand webcast

How to Boost Database Development Productivity on Linux, Docker, and Kubernetes with Microsoft SQL Server 2017 REGISTER >

Bruce Eckel's Thinking in Java Contents | Prev | Next

Three approaches to locating the performance-critical part of a program are:

1. Install your own instrumentation

“Profile” code by inserting explicit timing:

long start = System.currentTimeMillis();
   // Operation to be timed goes here
long time = System.currentTimeMillis() - start;

Have an infrequently-used method print cumulative times out to the console window with System.out.println( ). Since the compiler will ignore it when false, a static final boolean switch can turn the timing on and off so the code can efficiently be left in place in released code, ready for emergency use at any time. Even when more sophisticated profiling is available, this is a convenient way to time a specific task or operation.

System.currentTimeMillis( ) returns time in 1/1000ths of a second. However, some systems with time resolution less than a millisecond (such as a Windows PC) need to repeat an operation n times and divide the total time by n to get accurate estimates.

2. JDK profiling [2]

3. Special tools

Tips for measuring performance



Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • As all sorts of data becomes available for storage, analysis and retrieval - so called 'Big Data' - there are potentially huge benefits, but equally huge challenges...
  • The agile organization needs knowledge to act on, quickly and effectively. Though many organizations are clamouring for "Big Data", not nearly as many know what to do with it...
  • Cloud-based integration solutions can be confusing. Adding to the confusion are the multiple ways IT departments can deliver such integration...

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date