找出给定 java 进程的 -Xms 和 -Xmx 变量值的命令？
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Command to find out -Xms and -Xmx variable values for a given java process?
提问by Adon Smith
I have a java program, which i ran and figured out its process id with jps.
我有一个java程序，我运行它并用jps计算出它的进程ID。
How can i see what is the value of -Xms and -Xmx variable for this java process ?
我如何才能看到这个 java 进程的 -Xms 和 -Xmx 变量的值是多少？
回答by apangin
Try
尝试
jcmd <PID> VM.command_line
jcmd <PID> VM.flags
回答by SQL.injection
you can use jps and do it from the command line:
您可以使用 jps 并从命令行执行此操作：
jps # shows pids
jps -v <pid> # shows params
jps -v <localhost:pid> # the host must be indicated
if this is not enough you can do it programmatically inside the program to check the maximum amount of memory that the Java virtual machine will attempt to use:
如果这还不够，您可以在程序内部以编程方式执行此操作，以检查Java 虚拟机将尝试使用的最大内存量：
Runtime.getRuntime().maxMemory()
and you can also use use the class MemoryUsageto get the initial, used and max ammount that can be used for memory management.
您还可以使用MemoryUsage类来获取可用于内存管理的初始、已用和最大数量。
MemoryMXBean memoryBean = ManagementFactory.getMemoryMXBean();
memoryBean.getHeapMemoryUsage().getMax()
memoryBean.getHeapMemoryUsage().getUsed()
memoryBean.getHeapMemoryUsage().getInit()
回答by Hunter Zhao
I think jmapcommand will give you everything you want.
usage: jmap -heap {pid}
我认为jmap命令会给你你想要的一切。
用法：jmap -heap {pid}
root@BobServerStation:/usr/local $ jmap -heap 3280
Attaching to process ID 3280, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 24.65-b04
using thread-local object allocation.
Parallel GC with 8 thread(s)
Heap Configuration:
MinHeapFreeRatio = 0
MaxHeapFreeRatio = 100
MaxHeapSize = 4116709376 (3926.0MB)
NewSize = 1310720 (1.25MB)
MaxNewSize = 17592186044415 MB
OldSize = 5439488 (5.1875MB)
NewRatio = 2
SurvivorRatio = 8
PermSize = 21757952 (20.75MB)
MaxPermSize = 85983232 (82.0MB)
G1HeapRegionSize = 0 (0.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity = 65011712 (62.0MB)
used = 42273152 (40.3148193359375MB)
free = 22738560 (21.6851806640625MB)
65.0239021547379% used
From Space:
capacity = 10485760 (10.0MB)
used = 10479760 (9.994277954101562MB)
free = 6000 (0.0057220458984375MB)
99.94277954101562% used
To Space:
capacity = 10485760 (10.0MB)
used = 0 (0.0MB)
free = 10485760 (10.0MB)
0.0% used
PS Old Generation
capacity = 171442176 (163.5MB)
used = 376368 (0.3589324951171875MB)
free = 171065808 (163.1410675048828MB)
0.21953057805332568% used
PS Perm Generation
capacity = 22020096 (21.0MB)
used = 15401488 (14.688003540039062MB)
free = 6618608 (6.3119964599609375MB)
69.94287400018601% used
8464 interned Strings occupying 699456 bytes.
