java性能调优工具

最新推荐文章于 2022-06-14 11:38:21 发布

原创最新推荐文章于 2022-06-14 11:38:21 发布 · 1.2k 阅读

2 ·

CC 4.0 BY-SA版权

工具：

jstack

jstat

jmap

jhat

1、jstack 线程跟踪工具，用于打印指定Java进程的线程堆栈信息，如下示例:

"2019-04-12 18:21:24
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.20-b23 mixed mode):

\"Attach Listener\" #605 daemon prio=9 os_prio=0 tid=0x00007fc0a4001000 nid=0x8f618 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

\"pool-1-thread-200\" #604 prio=5 os_prio=0 tid=0x00007fbf08005800 nid=0x8f5af waiting on condition [0x00007fbc7cecf000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-199\" #603 prio=5 os_prio=0 tid=0x00007fbf940d9000 nid=0x8f4c5 waiting on condition [0x00007fbf007cd000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-198\" #602 prio=5 os_prio=0 tid=0x00007fbf10008000 nid=0x8f4c4 waiting on condition [0x00007fbd4c4c3000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-197\" #600 prio=5 os_prio=0 tid=0x00007fbfe0004000 nid=0x8f4c2 waiting on condition [0x00007fbd746c5000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-196\" #598 prio=5 os_prio=0 tid=0x00007fbea4033000 nid=0x8f3ad waiting on condition [0x00007fbceeae9000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-195\" #595 prio=5 os_prio=0 tid=0x00007fbf10007000 nid=0x8f215 waiting on condition [0x00007fbd753d2000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-194\" #594 prio=5 os_prio=0 tid=0x00007fbf10001800 nid=0x8f214 waiting on condition [0x00007fbd4e5e4000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-193\" #591 prio=5 os_prio=0 tid=0x00007fbedc02c800 nid=0x8f0ab waiting on condition [0x00007fbd4cbca000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"JSF-BZ-22001-12-T-24\" #590 daemon prio=5 os_prio=0 tid=0x00007fbe5c01d800 nid=0x8f0a5 waiting on condition [0x00007fbf003cb000]
   java.lang.Thread.State: WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x000000064cf8d6a8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:458)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.take(SynchronousQueue.java:924)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-192\" #589 prio=5 os_prio=0 tid=0x00007fbf18004800 nid=0x8f073 waiting on condition [0x00007fbd4e2e1000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-191\" #587 prio=5 os_prio=0 tid=0x00007fbec8006000 nid=0x8ef9d waiting on condition [0x00007fbcedcdb000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-190\" #584 prio=5 os_prio=0 tid=0x00007fbf9c001800 nid=0x8ee39 waiting on condition [0x00007fbd4cac9000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-189\" #583 prio=5 os_prio=0 tid=0x00007fbfac003800 nid=0x8ee07 waiting on condition [0x00007fbf00ed4000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"JSF-BZ-22001-12-T-23\" #580 daemon prio=5 os_prio=0 tid=0x00007fbe5c01d000 nid=0x8eca0 waiting on condition [0x00007fbcee2e1000]
   java.lang.Thread.State: WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x000000064cf8d6a8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:458)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.take(SynchronousQueue.java:924)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-188\" #579 prio=5 os_prio=0 tid=0x00007fbfcc00a000 nid=0x8ec06 waiting on condition [0x00007fbd4d8d7000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-187\" #578 prio=5 os_prio=0 tid=0x00007fbfcc009000 nid=0x8ec05 waiting on condition [0x00007fbd4e4e3000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-186\" #577 prio=5 os_prio=0 tid=0x00007fbfac006000 nid=0x8ebee waiting on condition [0x00007fbcee9e8000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-185\" #576 prio=5 os_prio=0 tid=0x00007fbf28001800 nid=0x8ebed waiting on condition [0x00007fbd4c7c6000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

\"pool-1-thread-184\" #569 prio=5 os_prio=0 tid=0x00007fbfcc008000 nid=0x8e7eb waiting on condition [0x00007fbc7d2d3000]
   java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000006496a87c8> (a java.util.concurrent.SynchronousQueue$TransferStack)
	at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

2、jstat 查看gc情况

示例如下：

  S0     S1     E      O      M     CCS    YGC     YGCT    FGC    FGCT     GCT   
  0.00 100.00  42.50  58.92  97.72  95.40    379   81.544     3    1.929   83.473
  0.00 100.00  42.83  58.92  97.72  95.40    379   81.544     3    1.929   83.473
  0.00 100.00  43.28  58.92  97.72  95.40    379   81.544     3    1.929   83.473
  0.00 100.00  46.72  58.92  97.72  95.40    379   81.544     3    1.929   83.473
  0.00 100.00  47.18  58.92  97.72  95.40    379   81.544     3    1.929   83.473

详细参考https://www.cnblogs.com/lizhonghua34/p/7307139.html

3、jmap

详细请看http://www.itboth.com/d/IjMjYj/jmap。

(1)使用jmap -heap pid查看进程堆内存使用情况，包括使用的GC算法、堆配置参数和各代中堆内存使用情况,示例如下：

Attaching to process ID 335303, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.20-b23

using thread-local object allocation.
Garbage-First (G1) GC with 53 thread(s)

Heap Configuration:
   MinHeapFreeRatio         = 40
   MaxHeapFreeRatio         = 70
   MaxHeapSize              = 3145728000 (3000.0MB)
   NewSize                  = 1363144 (1.2999954223632812MB)
   MaxNewSize               = 1887436800 (1800.0MB)
   OldSize                  = 5452592 (5.1999969482421875MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 21807104 (20.796875MB)
   CompressedClassSpaceSize = 1073741824 (1024.0MB)
   MaxMetaspaceSize         = 17592186044415 MB
   G1HeapRegionSize         = 1048576 (1.0MB)

Heap Usage:
G1 Heap:
   regions  = 3000
   capacity = 3145728000 (3000.0MB)
   used     = 2007923648 (1914.9052124023438MB)
   free     = 1137804352 (1085.0947875976562MB)
   63.83017374674479% used
G1 Young Generation:
Eden Space:
   regions  = 738
   capacity = 819986432 (782.0MB)
   used     = 773849088 (738.0MB)
   free     = 46137344 (44.0MB)
   94.37340153452685% used
Survivor Space:
   regions  = 81
   capacity = 84934656 (81.0MB)
   used     = 84934656 (81.0MB)
   free     = 0 (0.0MB)
   100.0% used
G1 Old Generation:
   regions  = 1100
   capacity = 2240806912 (2137.0MB)
   used     = 1149139904 (1095.9052124023438MB)
   free     = 1091667008 (1041.0947875976562MB)
   51.28241518026878% used

14338 interned Strings occupying 1548624 bytes.

(2)jmap histo

通过histo选项，打印当前java堆中各个对象的数量、大小。如果添加了live，只会打印活跃的对象。示例如下：

num     #instances         #bytes  class name
----------------------------------------------
   1:       1519872      121340120  [C
   2:       1518715       36449160  java.lang.String
   3:        601740       24069600  java.util.LinkedHashMap$Entry
   4:        565337       18090784  java.util.HashMap$Node
   5:          4185       14385904  [B
   6:         13774        9010056  [Ljava.util.HashMap$Node;
   7:         13635         654480  java.util.HashMap
   8:          4298         453744  java.lang.Class
   9:          5000         411304  [Ljava.lang.Object;
  10:         16528         396672  java.lang.Long
  11:         13029         312696  com.jd.bp.pojo.LogEntity
  12:         13029         208464  org.json.JSONObject
  13:          4368         139776  java.util.concurrent.ConcurrentHashMap$Node
  14:          2435         134184  [I
  15:           324         121824  java.lang.Thread
  16:          7426         118816  java.lang.Object
  17:           121         102704  [Ljava.util.concurrent.ConcurrentHashMap$Node;
  18:           849          95088  java.net.SocksSocketImpl
  19:          1001          88088  java.lang.reflect.Method
  20:          2660          85120  java.util.LinkedList
  21:          1507          84280  [Ljava.lang.String;
  22:           845          60840  org.apache.commons.pool2.impl.DefaultPooledObject
  23:           845          54080  com.jd.jim.cli.redis.jedis.Client
  24:          2207          52968  java.util.ArrayList
  25:          1622          51904  java.util.Hashtable$Entry
  26:           849          40752  java.net.SocketInputStream
  27:           849          40752  java.net.SocketOutputStream

(3)jmap -dump:[live,]format=b,file=<filename> <pid>

通过-dump选项，把java堆中的对象dump到本地文件，然后使用MAT进行分析。

如果添加了live，只会dump活跃的对象。

4、jhat

jhat -port 9999 dumpFileName

如果dump出来的文件过大，可能需要指定Xmx（jhat实际启动了一个web应用）。

jhat -J-Xmx1000m -port 9999 dumpFileName

详细请看https://www.cnblogs.com/huangfox/p/4354991.html