JVM 排查通用命令
1、查看某个进程的线程情况
(1) top -H -p pid
可以看到某个进程 pid 中的线程情况，包括占用CPU情况，内存只能看到整个进程占用内存情况，看不到单个线程占用内存情况
(2) ps -T -p pid
列举出某个进程下的所有线程，这个有助于帮助统计某个进程下的所有线程数，使用 ps -T -p pid |wc -l
(3) java 程序可以dump 处线程栈，查看各个线程的状态
jstack -l pid > thread.txt
如下图就是通过以上命令导出的某个进程下的线程栈信息。
2021-04-24 14:11:42 Full thread dump OpenJDK 64-Bit Server VM (25.242-b08 mixed mode): "Timer-for-arthas-dashboard-888ae817-de0e-425f-956e-b8c8317d0601" #39 daemon prio=10 os_prio=0 tid=0x00007f14b05f0800 nid=0x11c64 in Object.wait() [0x00007f14a2cfc000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.util.TimerThread.mainLoop(Timer.java:552) - locked <0x00000000e4c26060> (a java.util.TaskQueue) at java.util.TimerThread.run(Timer.java:505) Locked ownable synchronizers: - None "nioEventLoopGroup-2-2" #37 prio=10 os_prio=0 tid=0x00007f14ecc96000 nid=0xd9e6 runnable [0x00007f14bcaaa000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000e49128a8> (a io.netty.channel.nio.SelectedSelectionKeySet) - locked <0x00000000e4913980> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000e4912800> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:101) at io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:68) at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:803) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:457) at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "pool-1-thread-1" #35 prio=5 os_prio=0 tid=0x00007f14d02d6000 nid=0xd9b2 waiting on condition [0x00007f14bc1a5000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e493dfd8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "arthas-shell-server" #34 daemon prio=9 os_prio=0 tid=0x00007f14d02d2800 nid=0xd9b1 waiting on condition [0x00007f14bc2a6000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4918830> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "nioEventLoopGroup-3-1" #33 prio=10 os_prio=0 tid=0x00007f14d0284000 nid=0xd9b0 runnable [0x00007f14bc3a7000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000e4907498> (a io.netty.channel.nio.SelectedSelectionKeySet) - locked <0x00000000e4908e20> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000e4907400> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:101) at io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:68) at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:803) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:457) at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "nioEventLoopGroup-2-1" #32 prio=10 os_prio=0 tid=0x00007f14d0282800 nid=0xd9af runnable [0x00007f14bc4a8000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000e490c858> (a io.netty.channel.nio.SelectedSelectionKeySet) - locked <0x00000000e490d930> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000e490c7b0> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:101) at io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:68) at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:803) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:457) at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "job-timeout" #31 daemon prio=9 os_prio=0 tid=0x00007f14d0148000 nid=0xd9ae in Object.wait() [0x00007f14bc9a9000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x00000000e4916ec0> (a java.util.TaskQueue) at java.util.TimerThread.mainLoop(Timer.java:552) - locked <0x00000000e4916ec0> (a java.util.TaskQueue) at java.util.TimerThread.run(Timer.java:505) Locked ownable synchronizers: - None "Attach Listener" #29 daemon prio=9 os_prio=0 tid=0x00007f14c0001800 nid=0xd96a waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "DestroyJavaVM" #28 prio=5 os_prio=0 tid=0x00007f14ec04c800 nid=0x2acf waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "http-nio-8080-Acceptor" #26 daemon prio=5 os_prio=0 tid=0x00007f14ed17c800 nid=0x2d48 runnable [0x00007f14bd0b7000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:419) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:247) - locked <0x00000000e4958500> (a java.lang.Object) at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:463) at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:73) at org.apache.tomcat.util.net.Acceptor.run(Acceptor.java:95) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-ClientPoller" #25 daemon prio=5 os_prio=0 tid=0x00007f14ecfb8800 nid=0x2d47 runnable [0x00007f14bd1b8000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000e4977588> (a sun.nio.ch.Util$3) - locked <0x00000000e4977578> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000e4977530> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:708) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-10" #24 daemon prio=5 os_prio=0 tid=0x00007f14ed167800 nid=0x2d46 waiting on condition [0x00007f14bd2b9000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-9" #23 daemon prio=5 os_prio=0 tid=0x00007f14ed158000 nid=0x2d45 waiting on condition [0x00007f14bd3ba000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-8" #22 daemon prio=5 os_prio=0 tid=0x00007f14ed114000 nid=0x2d44 waiting on condition [0x00007f14bd4bb000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-7" #21 daemon prio=5 os_prio=0 tid=0x00007f14ed0a2800 nid=0x2d43 waiting on condition [0x00007f14bd5bc000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-6" #20 daemon prio=5 os_prio=0 tid=0x00007f14ed085800 nid=0x2d42 waiting on condition [0x00007f14bd6bd000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-5" #19 daemon prio=5 os_prio=0 tid=0x00007f14ed06a800 nid=0x2d41 waiting on condition [0x00007f14bd7be000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-4" #18 daemon prio=5 os_prio=0 tid=0x00007f14ed069800 nid=0x2d40 waiting on condition [0x00007f14bd8bf000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-3" #17 daemon prio=5 os_prio=0 tid=0x00007f14ed049000 nid=0x2d3f waiting on condition [0x00007f14bd9c0000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-2" #16 daemon prio=5 os_prio=0 tid=0x00007f14ece74800 nid=0x2d3c waiting on condition [0x00007f14bdac1000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-exec-1" #15 daemon prio=5 os_prio=0 tid=0x00007f14ed03a800 nid=0x2d35 waiting on condition [0x00007f14bdbc2000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4953ee0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "http-nio-8080-BlockPoller" #14 daemon prio=5 os_prio=0 tid=0x00007f14eca0d000 nid=0x2d2d runnable [0x00007f14bdcc3000] java.lang.Thread.State: RUNNABLE at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269) at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86) - locked <0x00000000e4975798> (a sun.nio.ch.Util$3) - locked <0x00000000e4975788> (a java.util.Collections$UnmodifiableSet) - locked <0x00000000e4975670> (a sun.nio.ch.EPollSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97) at org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:313) Locked ownable synchronizers: - None "container-0" #13 prio=5 os_prio=0 tid=0x00007f14ecf5e000 nid=0x2d09 waiting on condition [0x00007f14bdfc4000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.apache.catalina.core.StandardServer.await(StandardServer.java:570) at org.springframework.boot.web.embedded.tomcat.TomcatWebServer$1.run(TomcatWebServer.java:179) Locked ownable synchronizers: - None "Catalina-utility-2" #12 prio=1 os_prio=0 tid=0x00007f14ece79000 nid=0x2d08 waiting on condition [0x00007f14beac5000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4454f20> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1088) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "Catalina-utility-1" #11 prio=1 os_prio=0 tid=0x00007f14ecf50000 nid=0x2d07 waiting on condition [0x00007f14bf7d0000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000e4454f20> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Locked ownable synchronizers: - None "Service Thread" #7 daemon prio=9 os_prio=0 tid=0x00007f14ec1b5000 nid=0x2b0c runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "C1 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007f14ec1a2800 nid=0x2b0b waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x00007f14ec1a0000 nid=0x2b0a waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x00007f14ec193800 nid=0x2b09 runnable [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "Finalizer" #3 daemon prio=8 os_prio=0 tid=0x00007f14ec167000 nid=0x2b08 in Object.wait() [0x00007f14dc4f3000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x00000000e3ccec70> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144) - locked <0x00000000e3ccec70> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165) at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216) Locked ownable synchronizers: - None "Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007f14ec162800 nid=0x2b04 in Object.wait() [0x00007f14dc5f4000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x00000000e3ccea20> (a java.lang.ref.Reference$Lock) at java.lang.Object.wait(Object.java:502) at java.lang.ref.Reference.tryHandlePending(Reference.java:191) - locked <0x00000000e3ccea20> (a java.lang.ref.Reference$Lock) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153) Locked ownable synchronizers: - None "VM Thread" os_prio=0 tid=0x00007f14ec159000 nid=0x2afe runnable "GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00007f14ec05f800 nid=0x2ae6 runnable "GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00007f14ec061000 nid=0x2ae8 runnable "VM Periodic Task Thread" os_prio=0 tid=0x00007f14ec1ca000 nid=0x2b0d waiting on condition JNI global references: 1044
2、top 命令查看整个系统的内存、CPU情况，但是执行该命令之后，没有看到内存等单位信息，此时可以通过 按键进行内存单位切换
(1) 按 E，将 top 顶部展示的全局内存使用情况的单位 转换成 ｍ、ｇ 等单位；
(2) 按 e，将 top 下部按照进程展示的内存使用情况的单位 转换成 m、g 等单位；
