-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
- 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] |