-XX:[+|-]HitachiVerboseGCPrintThreadCount (Option to output the number of threads)
- Organization of this page
Format
- -XX:+HitachiVerboseGCPrintThreadCount
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This option outputs the number of Java threads.
- -XX:-HitachiVerboseGCPrintThreadCount
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This option does not output the number of Java threads.
Description
Specifies whether to output the number of Java threads to the JavaVM log file in order to monitor the number of Java threads.
A thread individually allocates the memory to be used for a stack as C heap. Therefore, if the number of threads increase, the allocated C heap amount also increases in proportion to the number of threads. By specifying the -XX:+HitachiVerboseGCPrintThreadCount option, you can monitor the number of Java threads as well as understand the amount of C heap that is allocated.
- Default value
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-XX:+HitachiVerboseGCPrintThreadCount
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- Prerequisite options
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-XX:+HitachiVerboseGC
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Output format
[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]
The output contents are explained below. Note that the following explains the items output by this option. For items other than explained below, see the output format described in -XX:[+|-]HitachiVerboseGC (Option for extended verbosegc information output).
- thread_count
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Specifies the number of Java threads.
Examples of output
[VGC]<Wed Jan 27 13:03:36 2010>(Skip Full:0,Copy:0)[GC 489K->152K(3520K), 0.0156080 secs][DefNew::Eden: 489K->0K(2048K)][DefNew::Survivor: 0K->63K(64K)][Tenured: 0K->88K(1408K)][Metaspace: 3634K(4492K, 4492K)->3634K(4492K, 4492K)][class space: 356K(388K, 388K)->356K(388K, 388K)][cause:ObjAllocFail][IM: 729K, 928K, 0K][TC: 509]