jstack命令解析
jstack用法
/opt/java8/bin/jstack Usage: jstack [-l] <pid> (to connect to running process) 连接活动线程 jstack -F [-m] [-l] <pid> (to connect to a hung process) 连接阻塞线程 jstack [-m] [-l] <executable> <core> (to connect to a core file) 连接dump的文件 jstack [-m] [-l] [server_id@]<remote server IP or hostname> (to connect to a remote debug server) 连接远程服务器 Options: -F to force a thread dump. Use when jstack <pid> does not respond (process is hung) -m to print both java and native frames (mixed mode) -l long listing. Prints additional information about locks -h or -help to print this help message
jstack查看输出
/opt/java8/bin/jstack -l 28367 2019-06-25 15:04:46 Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.77-b03 mixed mode): "Attach Listener" #453 daemon prio=9 os_prio=0 tid=0x00007f9f94001000 nid=0xf30 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "grpc-default-executor-263" #452 daemon prio=5 os_prio=0 tid=0x00007f9f4c01f800 nid=0x9aa waiting on condition [0x00007f9f398bd000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000007400243f0> (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) Locked ownable synchronizers: - None "http-bio-8080-exec-10" #235 daemon prio=5 os_prio=0 tid=0x0000000001bcc800 nid=0x3c13 waiting on condition [0x00007f9f384a9000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x0000000743d26638> (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:104) at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:32) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) Locked ownable synchronizers: - None
jstack统计线程数
/opt/java8/bin/jstack -l 28367 | grep 'java.lang.Thread.State' | wc -l
jstack检测死锁
public class DeathLock { private static Lock lock1 = new ReentrantLock(); private static Lock lock2 = new ReentrantLock(); public static void deathLock() { Thread t1 = new Thread() { @Override public void run() { try { lock1.lock(); TimeUnit.SECONDS.sleep(1); lock2.lock(); } catch (InterruptedException e) { e.printStackTrace(); } } }; Thread t2 = new Thread() { @Override public void run() { try { lock2.lock(); TimeUnit.SECONDS.sleep(1); lock1.lock(); } catch (InterruptedException e) { e.printStackTrace(); } } }; t1.setName("mythread1"); t2.setName("mythread2"); t1.start(); t2.start(); } public static void main(String[] args) { deathLock(); } }
死锁日志
"mythread2" #12 prio=5 os_prio=0 tid=0x0000000058ef7800 nid=0x1ab4 waiting on condition [0x0000000059f8f000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000d602d610> (a java.util.concurrent.lock s.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInt errupt(AbstractQueuedSynchronizer.java:836) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(A bstractQueuedSynchronizer.java:870) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Abstrac tQueuedSynchronizer.java:1199) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLo ck.java:209) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:285) at DeathLock$2.run(DeathLock.java:34) Locked ownable synchronizers: - <0x00000000d602d640> (a java.util.concurrent.locks.ReentrantLock$Nonfa irSync) "mythread1" #11 prio=5 os_prio=0 tid=0x0000000058ef7000 nid=0x3e68 waiting on condition [0x000000005947f000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000d602d640> (a java.util.concurrent.lock s.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInt errupt(AbstractQueuedSynchronizer.java:836) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(A bstractQueuedSynchronizer.java:870) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Abstrac tQueuedSynchronizer.java:1199) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLo ck.java:209) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:285) at DeathLock$1.run(DeathLock.java:22) Locked ownable synchronizers: - <0x00000000d602d610> (a java.util.concurrent.locks.ReentrantLock$Nonfa irSync) Found one Java-level deadlock: ============================= "mythread2": waiting for ownable synchronizer 0x00000000d602d610, (a java.util.concurrent.l ocks.ReentrantLock$NonfairSync), which is held by "mythread1" "mythread1": waiting for ownable synchronizer 0x00000000d602d640, (a java.util.concurrent.l ocks.ReentrantLock$NonfairSync), which is held by "mythread2" Java stack information for the threads listed above: =================================================== "mythread2": at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000d602d610> (a java.util.concurrent.lock s.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInt errupt(AbstractQueuedSynchronizer.java:836) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(A bstractQueuedSynchronizer.java:870) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Abstrac tQueuedSynchronizer.java:1199) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLo ck.java:209) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:285) at DeathLock$2.run(DeathLock.java:34) "mythread1": at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000d602d640> (a java.util.concurrent.lock s.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInt errupt(AbstractQueuedSynchronizer.java:836) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(A bstractQueuedSynchronizer.java:870) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Abstrac tQueuedSynchronizer.java:1199) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLo ck.java:209) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:285) at DeathLock$1.run(DeathLock.java:22) Found 1 deadlock.
jstack检测cpu高
步骤一:查看cpu占用高进程
top Mem: 16333644k total, 9472968k used, 6860676k free, 165616k buffers Swap: 0k total, 0k used, 0k free, 6665292k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 17850 root 20 0 7588m 112m 11m S 100.7 0.7 47:53.80 java 1552 root 20 0 121m 13m 8524 S 0.7 0.1 14:37.75 AliYunDun 3581 root 20 0 9750m 2.0g 13m S 0.7 12.9 298:30.20 java 1 root 20 0 19360 1612 1308 S 0.0 0.0 0:00.81 init 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd 3 root RT 0 0 0 0 S 0.0 0.0 0:00.14 migration/0
步骤二:查看cpu占用高线程
top -H -p 17850 top - 17:43:15 up 5 days, 7:31, 1 user, load average: 0.99, 0.97, 0.91 Tasks: 32 total, 1 running, 31 sleeping, 0 stopped, 0 zombie Cpu(s): 3.7%us, 8.9%sy, 0.0%ni, 87.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 16333644k total, 9592504k used, 6741140k free, 165700k buffers Swap: 0k total, 0k used, 0k free, 6781620k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 17880 root 20 0 7588m 112m 11m R 99.9 0.7 50:47.43 java 17856 root 20 0 7588m 112m 11m S 0.3 0.7 0:02.08 java 17850 root 20 0 7588m 112m 11m S 0.0 0.7 0:00.00 java 17851 root 20 0 7588m 112m 11m S 0.0 0.7 0:00.23 java 17852 root 20 0 7588m 112m 11m S 0.0 0.7 0:02.09 java 17853 root 20 0 7588m 112m 11m S 0.0 0.7 0:02.12 java 17854 root 20 0 7588m 112m 11m S 0.0 0.7 0:02.07 java
步骤三:转换线程ID
printf "%x\n" 17880
45d8
步骤四:定位cpu占用线程
jstack 17850|grep 45d8 -A 30 "pool-1-thread-11" #20 prio=5 os_prio=0 tid=0x00007fc860352800 nid=0x45d8 runnable [0x00007fc8417d2000] java.lang.Thread.State: RUNNABLE at java.io.FileOutputStream.writeBytes(Native Method) at java.io.FileOutputStream.write(FileOutputStream.java:326) at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82) at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140) - locked <0x00000006c6c2e708> (a java.io.BufferedOutputStream) at java.io.PrintStream.write(PrintStream.java:482) - locked <0x00000006c6c10178> (a java.io.PrintStream) at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221) at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:291) at sun.nio.cs.StreamEncoder.flushBuffer(StreamEncoder.java:104) - locked <0x00000006c6c26620> (a java.io.OutputStreamWriter) at java.io.OutputStreamWriter.flushBuffer(OutputStreamWriter.java:185) at java.io.PrintStream.write(PrintStream.java:527) - eliminated <0x00000006c6c10178> (a java.io.PrintStream) at java.io.PrintStream.print(PrintStream.java:597) at java.io.PrintStream.println(PrintStream.java:736) - locked <0x00000006c6c10178> (a java.io.PrintStream) at com.demo.guava.HardTask.call(HardTask.java:18) at com.demo.guava.HardTask.call(HardTask.java:9) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) "pool-1-thread-10" #19 prio=5 os_prio=0 tid=0x00007fc860345000 nid=0x45d7 waiting on condition [0x00007fc8418d3000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000006c6c14178> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
文章转载至:https://www.jianshu.com/p/8d5782bc596e