-XX:[+|-]PrintCodeCacheInfo (Option for the output of the code cache area information)

Organization of this page

Format
Description
Output format
Examples of output
Notes

Format

-XX:+PrintCodeCacheInfo

This option outputs the amount of code cache area used.

This option also outputs a message informing the user that the usage of the code cache area has reached the threshold value.

-XX:-PrintCodeCacheInfo

This option does not output the amount of code cache area used.

Also, this option does not output the message informing the user that the usage of the code cache area has reached the threshold value.

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Description

Specify whether to output the amount of code cache area used and the message informing the user that the usage has reached the threshold value, to the JavaVM log file.

For details about the code cache area, see 7.2.6 Configuration of memory space used by JavaVM when using serial GC and JavaVM options in the Application Server System Design Guide.

If this option is enabled, the amount of code cache area used is output to the extended verbosegc information when a GC occurs. Also, a message is output when the amount of code cache area used reaches the threshold value.

The threshold value is maximum-size-of-code-cache-area ×value-of--XX:CodeCacheInfoPrintRatio-option / 100.

Even if the -XX:-HitachiVerboseGC option is specified, the amount of code cache area used is output to the extended verbosegc information output by the -v option and -s option of the javagc command.

Default value

-XX:+PrintCodeCacheInfo

Prerequisite option

-XX:+HitachiVerboseGC

Related options

-XX:+HitachiCommaVerboseGC
-XX:CodeCacheInfoPrintRatio

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Output format

The output format of the amount of code cache area used is as follows:

[id] date (Skip Full:full_count, Copy:copy_count, Inc:inc_count) [gc_kind gc_info, gc_time secs][Eden: eden_info][Survivor: survivor_info][Tenured: tenured_info] [Metaspace: metaspace_info][class space: class_space_info][cause: cause_info] [User: user_cpu secs][Sys: system_cpu secs][IM: jvm_alloc_size, mmap_total_size, malloc_total_size][TC: thread_count][DOE: doe_alloc_size, called_count][CCI: cc_used_sizeK, cc_max_sizeK, cc_infoK]

The output contents are as follows. Note that the items output by this option are described here. For items other than those described here, see the output format in -XX:[+|-]HitachiVerboseGC (Option for extended verbosegc information output).

cc_used_size: Specifies the size of the code cache area used when the GC occurs. The unit is kilobyte.
cc_max_size: Specifies the maximum size of the code cache area. The unit is kilobyte.
cc_info: Specifies the maintenance information.

The following is the output format of the message informing the user that the usage of the code cache area has reached the threshold value:

[cc_id]<cc_date>CodeCache usage has exceeded the threshold.[cc_used_sizeK, cc_max_sizeK, cc_infoK]

The contents output in the message are as follows:

cc_id: Specifies the CCI (identifier of the JavaVM log file).
cc_date: Specifies the date and time when the JIT compilation was executed.
cc_used_size: Specifies the used size of the code cache area after the JIT compilation. The unit is kilobyte.
cc_max_size: Specifies the maximum size of the code cache area. The unit is kilobyte.
cc_info: Specifies the maintenance information.

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Examples of output

The following is an example of output of the amount of code cache area used:

[VGC]<Wed Mar 17 00:42:30 2004>(Skip Full:0,Copy:0)[Full GC 149K->149K(1984K), 0.0786038 secs][DefNew::Eden: 264K->0K(512K)][DefNew::Survivor: 0K->63K(64K)][Tenured: 85K->149K(1408K)][Metaspace: 3634K(4492K, 4492K)->3634K(4492K, 4492K)][class space: 356K(388K, 388K)->356K(388K, 388K)][cause:System.gc][User: 0.0156250 secs][Sys: 0.0312500 secs][IM: 729K, 928K, 0K][TC: 509][DOE: 16K, 170][CCI: 2301K, 49152K, 2304K]

The following is an example of output of the message informing the user that the usage of the code cache area has reached the threshold value:
```
[CCI]<Wed Dec 26 14:27:53 2012>CodeCache usage has exceeded the threshold.[39358K, 49152K, 39360K]
```

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Notes

If usage of the code cache area is changed when the threshold value is reached, no message is output even if the JIT compilation is executed for the Java method.

On the other hand, after the usage of the code cache area drops to less than the threshold value, the message is output when the usage of the code cache area again reaches the threshold value due to the JIT compilation of the Java method.
The code cache area used by the system is a maximum of 2 megabyte. Therefore, depending on the usage of the code cache area of the system, the code cache area might deplete even if the maximum area is not used.

Also, if a large value is specified as the threshold value for the usage of the code cache area, the code cache area might deplete before the message is output. If you want the message to be output before the code cache area depletes, specify the value for -XX:CodeCacheInfoPrintRatio (Option for specifying the usage rate of the code cache area) in such a way that the value of "maximum-size-of-code-cache-area - threshold-value" is 4 megabyte or more.

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