HPjmeter 4.3 User's Guide

$ java ... -XX:+PrintGCDetails -Xloggc:filename
Use these additional options to obtain more data on GC activity in the eden space, the survivor
space, the old generation, and the permanent generation.
NOTE:
Using -XX:+PrintGCDetails and -XX:+PrintHeapAtGC Together
Some JVMs improperly mix the output from these two options, resulting in a data file that cannot
be parsed properly by HPjmeter. We recommend using only one of the two options.
When using the G1 collector, HPjmeter 4.3 only supports the output from –XX:+UseG1GC, HPjmeter
does not support the combinations “–XX:+UseG1GC –XX:+PrintGCDetails” or
“-XX:+UseG1GC –XX:+PrintHeapAtGC”.
To see the availability in HPjmeter of metrics derived from -Xloggc data, see -Xverbosegc and
-Xloggc Options and Their Corresponding Metrics (page 101).
Naming GC Data Files
The following table shows the file name formats used by default when naming files containing
garbage collection data. You may want to follow this convention when naming GC data files, but
it is not required.
Table 11 Default File Name Suffixes for GC Data
File Name SuffixOption
.vgc-Xverbosegc
.vgc-Xloggc
-Xverbosegc and -Xloggc Options and Their Corresponding Metrics
The following metrics or features are available depending on the option used to collect data.
Table 12 Available Metrics from -Xverbosegc and -Xloggc Garbage Collection Data
-Xloggc-XverbosegcMetric
NoYesAllocation Site Statistics (page 185)†
YesYesHeap Usage After GC (page 181)
YesYesDuration (Stop the World) (page 182)
YesYesCumulative Allocation (page 183)
YesYesCreation Rate (page 184)
YesYesCumulative GC duration*
YesYesHeap usage before GC*
YesYesHeap capacity*
YesYesReclaimed bytes*
NoYesPromoted bytes*
YesYesPercentage of Time in GC*
† Requires the additional option -XX:+PrintAllocStatistics. See Collecting Allocation
Site Statistics for Viewing in HPjmeter (page 98) for an example of command syntax.
* You can create a graphical view of these metrics using the User-Defined X-Y Axes
visualizer (page 191). Other raw metrics are also available for graphing from this visualizer.
-Xverbosegc and -Xloggc Options and Their Corresponding Metrics 101