visualVM中各个名词的解释

Process Memory Parameters	Description
Eden Space (Heap Memory)	Pool from which memory is initially allocated for most objects
Survivor Space (Heap Memory)	Pool containing objects that have survived GC of eden space.
Tenured Generation (Heap Memory)	Pool containing objects that have existed for some time in the survivor space.
Permanent Generation (Non-Heap)	Holds all the reflective data of the virtual machine itself, such as class and method objects. With JVMs that use class data sharing, this generation is divided into read-only and read-write areas
Code Cache (Non-Heap)	Memory used for compilation and storage of native code.

 

Thread Parameters

 

Live Threads	Number of live threads currently running
Daemon Threads	Number of daemon threads currently running
Runnable Threads	A thread executing in the Java virtual machine is in this state
Blocked Threads	A thread that is blocked waiting for a monitor lock is in this state
Waiting Threads	A thread that is waiting indefinitely for another thread to perform a particular action is in this state.
Timed waiting Threads	A thread that is waiting for another thread to perform an action for up to a specified waiting time is in this state
Total threads started	Total number of threads created and also started since the Java virtual machine started
Peak Threads	Peak live thread count since the Java virtual machine started or peak was reset
Deadlocked	Number of threads that are in deadlock waiting to acquire object monitors

 

Virtual Memory Parameters

 

 

Classes loaded	Number of classes loaded
Classes Unloaded	Number of classes unloaded
GC time	Time taken to perform garbage collection
Compile time	Time spent in just-in-time (JIT) compilation
Max file descriptor	Maximum permissible open file descriptor. Available only for UNIX.
Open file descriptor	Current count of open file descriptors. Available only for UNIX.

 

 

Host Memory Parameters

 

 

Total Physical Memory	Total amount of physical memory in Megabytes
Free Physical Memory	The amount of free physical memory in Megabytes
Total Swap Space	Total amount of swap space in Megabytes
Committed Virtual Memory	The amount of virtual memory that is guaranteed to be available to the running process in Megabytes

 

 

 

 Garbage Collector

 

 

Time Spent/Min	Total number of collections that have occurred
Collections/Min	Approximate collection elapsed time in milliseconds
Thread Count	Number of threads used for Garbage Collector
Last Start Time	Start time of this GC
Last End Time	End time of this GC
Memory usage before GC	Memory usage of all memory pools at the beginning of this GC
Memory usage after GC	Memory usage of all memory pools at the end of this GC

 

 

Configuration

 

Uptime	The uptime of the Java virtual machine
Java Virtual Machine	The Java virtual machine implementation name
Vendor	The Java virtual machine implementation vendor
Process ID	The process identifier is a number used by some operating system kernels to uniquely identify a process
Name	The name representing the running Java virtual machine
VM arguments	The input arguments passed to the Java virtual machine which does not include the arguments to the main method
Class path	The Java class path that is used by the system class loader to search for class files
Library path	The Java library path
Library path	The boot class path that is used by the bootstrap class loader to search for class files
JIT compiler	The name of the Just-in-time (JIT) compiler
Objects Pending for finalization	The approximate number of objects for which finalization is pending
Operating System	The name of the operating system
Architecture	The operating system architecture
Processors	The number of processors available to the Java virtual machine