HPjmeter 4.3 User's Guide

Using Specialized Garbage Collection Displays
GC data displays are available immediately on opening a .vgc file that was generated by running
your application with -Xverbosegc or -Xloggc options. This data is presented in the following
visualizers:
• Heap Usage After GC (page 181)
• Duration (Stop the World) (page 182)
• Cumulative Allocation (page 183)
• Creation Rate (page 184)
• Allocation Site Statistics (page 185)
• User-Defined X-Y Axes (page 191)
• Multiple User-Defined (page 192)
• Glance Data (page 194)
• Glance System Call Data (page 198)
See also:
• Basic Garbage Collection Concepts (page 103)
• Profiling Applications (page 69)
• Using Visualizer Tool Bars (page 201)
• Viewing Profiling or GC Data in HPjmeter (page 160)
For an explanation of Java memory terminology, see the Sun Developer Network publication
Memory Management in the Java HotSpot™ Virtual Machine (.pdf)
For an explanation of Java memory terminology, see the Sun Developer Network publication
Memory Management in the Java HotSpot™ Virtual Machine
(http://java.sun.com/j2se/reference/whitepapers/memorymanagement_whitepaper.pdf)
Heap Usage After GC
This visualizer shows heap usage in the eden space and in the old, survivor, and permanent
generations after each garbage collection. When viewed with consideration of the type of each
event, this graph provides a general picture of the heap resources minimally required by an
application.
NOTE:
Difference in Display of Garbage Collection in the Heap Monitor and the Heap Usage After GC
Visualizers
Monitoring visualizers like the Heap Monitor show only object data from the eden, survivor, and
old generation spaces. Visualizers that display GC data, like the Heap Usage After GC visualizer,
show object data from the permanent generation, as well as from the eden, survivor, and old
generation spaces.
Using Specialized Garbage Collection Displays 181