-XX:[+|-]HitachiVerboseGCPrintTenuringDistribution (Age distribution output option of Survivor area)

Format

-XX:+HitachiVerboseGCPrintTenuringDistribution
This option outputs the age distribution of Survivor area that is output when specifying -XX:+PrintTenuringDistribution to the JavaVM log file.
-XX:-HitachiVerboseGCPrintTenuringDistribution
This option does not output the age distribution of Survivor area that is output when specifying -XX:+PrintTenuringDistribution to the JavaVM log file.

Description

Specify whether to output the age distribution of the Survivor area that is output when specifying -XX:+PrintTenuringDistribution to the JavaVM log file.

Default value
  • -XX:-HitachiVerboseGCPrintTenuringDistribution
Prerequisite options
  • -XX:+HitachiVerboseGC
Related option
  • -XX:+PrintTenuringDistribution
  • -XX:+HitachiVerboseGCPrintDate
  • -XX:+HitachiCommaVerboseGC

Output format

[id]date[Desired survivor:size bytes][New threshold:value][MaxTenuringThreshold: max_value][age1:total_age1][age2:total_age2]...[agen:total_agen]

The following is a description of the output contents:

id
PTD (JavaVM log file identifier).
date
Indicates the date and time for starting garbage collection.
size
Indicates the object target size in Survivor area after garbage collection.
value
Specifies the tenuring threshold value of the Java objects promoted to the Tenured area during the next copy garbage collection.
This value is set up dynamically for each copy garbage collection, based on the values specified in the -XX:MaxTenuringThreshold=value option, the memory size of the Survivor area, and the -XX:TargetSurvivorRatio=value option.
The tenured Java objects more than the value in value are promoted to the Tenured area in the next copy garbage collection.
max_value
Maximum (value specified in the MaxTenuringThreshold option) tenuring threshold value (value) of the Java objects promoted to the Tenured area during copy garbage collection.
The value is set up dynamically for each copy garbage collection; however, does not exceed the max_value value.
Also, the Java objects for which tenuring is greater than the max_value value are definitely promoted to the Tenured area during the next copy garbage collection.
total_age1
Indicates total number of bytes of a 1 year old object.
total_age2
Indicates total number of bytes of a 1 to 2 year old object.
total_agen
Indicates total number of bytes of a 1 to n year old object.
If n is close to max_value, it means that an object with a long life exists.

Examples of output

[PTD]<Wed Jan 28 17:47:10 2009>[Desired survivor:32768 bytes][New threshold:30][MaxTenuringThreshold:30][age1:6872][age2:9632][age3:25632]