HPjmeter 4.3 User's Guide

Related Topics
• Identifying Abnormal Thread Termination (page 54)
• Identifying Multiple Short-lived Threads (page 55)
• Identifying Excessive Lock Contention (page 55)
• Change Color Selection for Histogram Display (page 210)
Lock Contention
Provides lock contention statistics.
The percentages for each method represent how much of the total lock contention observed occurred
in that method. For example, if there was a single instance of lock contention during a run, that
method would show 100 percent. Therefore, methods that show a high percentage of lock contention
may not be a problem, unless you see a significant amount lock contention in your application.
Lock contention can be detected either in synchronized methods, or in methods that contain
synchronized blocks.
Guidelines
• Lock contention in a running application does not necessarily indicate a problem.
• If you suspect a lock contention problem with your application, you should look more closely
at the highest-ranked methods in the Lock Contention display.
• The Thread Histogram can also help you determine if there is significant lock contention. Other
system-level tools can also provide information to determine if there is excessive lock contention.
Details
This metric uses sampling to determine the level of lock contention. Therefore, this display shows
percentages of time wasted over the sampling period, not actual time wasted in lock contention.
The reported data is cumulative over the lifetime of the session.
Figure 48 Monitoring Metric: Lock Contention
Using Monitoring Displays 153