Details

•For HP Java 1.5.0.12 and later or 6.0.01 or later, this visualizer distinguishes between major and minor garbage collections such as full GC and scavenge.

Related Topics

•GC Duration Notification (page 110)

•Checking for Proper Heap Sizing (page 43)

•Reviewing the Percentage of Time Spent in Garbage Collection (page 41)

•Allocated Object Statistics by Class (page 127)

•Identifying Excessive Object Allocation (page 44)

•Basic Garbage Collection Concepts (page 87)

Percentage of Time Spent in Garbage Collection

The percentage is an estimated value of the time spent in garbage collection.

Guidelines

•The horizontal red line shows the current average percentage of time spent in garbage collection.

•An almost steady value of 5 percent or less is considered low and acceptable.

•Sustained values larger than 10 percent suggest room for improvement.

Details

Here are two possible ways to make improvements:

•Tune the heap parameters for better performance. For HP HotSpot VM, run your application with the -Xverbosegcoption and view the results in HPjmeter.

•If the heap has been already tuned, you can decrease the application pressure on the heap, that is, decrease the rate of object allocations, by trying these alternatives:

—Reusing objects

—Changing memory-inefficient algorithms

Object allocation statistics can help identify areas for improvement.

Using Monitoring Displays 125