概述
jstack是jdk自带的线程堆栈分析工具,使用该命令可以查看或导出 java 应用程序中线程堆栈信息。jstack用于生成java虚拟机当前时刻的线程快照。线程快照是当前java虚拟机内每一条线程正在执行的方法堆栈的集合,生成线程快照的主要目的是定位线程出现长时间停顿的原因,如线程间死锁、死循环、请求外部资源导致的长时间等待等。 线程出现停顿的时候通过jstack来查看各个线程的调用堆栈,就可以知道没有响应的线程到底在后台做什么事情,或者等待什么资源。 如果java程序崩溃生成core文件,jstack工具可以用来获得core文件的java stack和native stack的信息,从而可以轻松地知道java程序是如何崩溃和在程序何处发生问题。另外,jstack工具还可以附属到正在运行的java程序中,看到当时运行的java程序的java stack和native stack的信息, 如果现在运行的java程序呈现hung的状态,jstack是非常有用的。
一、jstack用法
[root@smdw tang]# jstack
Usage:
jstack [-l] <pid>
(to connect to running process)
jstack -F [-m] [-l] <pid>
(to connect to a hung process)
jstack [-m] [-l] <executable> <core>
(to connect to a core file)
jstack [-m] [-l] [server_id@]<remote server IP or hostname>
(to connect to a remote debug server)
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
二、jstack查看输出
[root@smdw tang]# jps -l
640 sun.tools.jps.Jps
2465 /usr/local/whistle/webapps/EurekaServer/lib/EurekaServer-0.0.1.jar
14417 /usr/local/whistle/webapps/dataAnalysis/lib/dataAnalysis.jar
6753 sun.tools.jstatd.Jstatd
21380 com.weishao.standard.StandardConverterApplication
4696 kafka.Kafka
1882 org.apache.zookeeper.server.quorum.QuorumPeerMain
12830 com.weishao.dbswitch.webapi.WebServiceApplication
[root@smdw tang]# jstack -l 21380
2020-03-07 14:11:25
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.112-b15 mixed mode):
"Attach Listener" #107 daemon prio=9 os_prio=0 tid=0x00007faf94001000 nid=0x7f7c waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
Locked ownable synchronizers:
- None
"RMI TCP Connection(59)-172.16.68.35" #106 daemon prio=5 os_prio=0 tid=0x00007faf5800b000 nid=0x7f2c runnable [0x00007faecbffd000]
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:170)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
- locked <0x0000000758b002a8> (a java.io.BufferedInputStream)
at java.io.FilterInputStream.read(FilterInputStream.java:83)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:550)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$741/422928510.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Locked ownable synchronizers:
- <0x0000000769c643b8> (a java.util.concurrent.ThreadPoolExecutor$Worker)
................
Locked ownable synchronizers:
- None
"VM Thread" os_prio=0 tid=0x00007fb0488ac000 nid=0x53a5 runnable
"Gang worker#0 (Parallel GC Threads)" os_prio=0 tid=0x00007fb048025800 nid=0x5386 runnable
三、jstack统计线程数
[root@smdw tang]# jstack -l 21380 | grep 'java.lang.Thread.State' | wc -l
63
四、jstack检测死锁
(1)死锁代码
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();
}
}
(2)jstack分析
"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.
五、利用jstack检测cpu飙高问题
步骤一:查看cpu占用高进程
[root@smdw tang]#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
[root@smdw tang]#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 "%xn" 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)
此外,推荐一个阿里牛人写的排查脚本show-busy-java-threads工具:https://github.com/oldratlee/useful-scripts
最后
以上就是缥缈路人为你收集整理的jstack命令及其死锁、CPU飙高问题排查使用一、jstack用法二、jstack查看输出三、jstack统计线程数四、jstack检测死锁的全部内容,希望文章能够帮你解决jstack命令及其死锁、CPU飙高问题排查使用一、jstack用法二、jstack查看输出三、jstack统计线程数四、jstack检测死锁所遇到的程序开发问题。
如果觉得靠谱客网站的内容还不错,欢迎将靠谱客网站推荐给程序员好友。
发表评论 取消回复