### 支持一键展示当前最忙的前N个线程并打印堆栈： `thread -n 3`{{execute T2}} ```bash $ thread -n 3 "as-command-execute-daemon" Id=29 cpuUsage=75% RUNNABLE at sun.management.ThreadImpl.dumpThreads0(Native Method) at sun.management.ThreadImpl.getThreadInfo(ThreadImpl.java:440) at com.taobao.arthas.core.command.monitor200.ThreadCommand$1.action(ThreadCommand.java:58) at com.taobao.arthas.core.command.handler.AbstractCommandHandler.execute(AbstractCommandHandler.java:238) at com.taobao.arthas.core.command.handler.DefaultCommandHandler.handleCommand(DefaultCommandHandler.java:67) at com.taobao.arthas.core.server.ArthasServer$4.run(ArthasServer.java:276) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:745) Number of locked synchronizers = 1 - java.util.concurrent.ThreadPoolExecutor$Worker@6cd0b6f8 "as-session-expire-daemon" Id=25 cpuUsage=24% TIMED_WAITING at java.lang.Thread.sleep(Native Method) at com.taobao.arthas.core.server.DefaultSessionManager$2.run(DefaultSessionManager.java:85) "Reference Handler" Id=2 cpuUsage=0% WAITING on java.lang.ref.Reference$Lock@69ba0f27 at java.lang.Object.wait(Native Method) - waiting on java.lang.ref.Reference$Lock@69ba0f27 at java.lang.Object.wait(Object.java:503) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133) ``` ### 当没有参数时，显示所有线程的信息。 `thread`{{execute T2}} ```bash $ thread Threads Total: 16, NEW: 0, RUNNABLE: 7, BLOCKED: 0, WAITING: 5, TIMED_WAITING: 4, TERMINATED: 0 ID NAME GROUP PRIORITY STATE %CPU TIME INTERRUPTE DAEMON 30 as-command-execute-daemon system 9 RUNNABLE 72 0:0 false true 23 as-session-expire-daemon system 9 TIMED_WAIT 27 0:0 false true 22 Attach Listener system 9 RUNNABLE 0 0:0 false true 11 pool-2-thread-1 main 5 TIMED_WAIT 0 0:0 false false 12 Thread-2 main 5 RUNNABLE 0 0:0 false true 13 pool-3-thread-1 main 5 TIMED_WAIT 0 0:0 false false 25 as-selector-daemon system 9 RUNNABLE 0 0:0 false true 14 Thread-3 main 5 TIMED_WAIT 0 0:0 false false 26 pool-5-thread-1 system 5 WAITING 0 0:0 false false 15 Thread-4 main 5 RUNNABLE 0 0:0 false false 1 main main 5 WAITING 0 0:2 false false 2 Reference Handler system 10 WAITING 0 0:0 false true 3 Finalizer system 8 WAITING 0 0:0 false true 4 Signal Dispatcher system 9 RUNNABLE 0 0:0 false true 20 NonBlockingInputStreamThread main 5 WAITING 0 0:0 false true 21 Thread-8 main 5 RUNNABLE 0 0:0 false true ``` ### thread id， 显示指定线程的运行堆栈 查看线程ID 16的栈： `thread 16`{{execute T2}} ```bash $ thread 1 "main" Id=1 WAITING on java.util.concurrent.CountDownLatch$Sync@29fafb28 at sun.misc.Unsafe.park(Native Method) - waiting on java.util.concurrent.CountDownLatch$Sync@29fafb28 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836) at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:997) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304) at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:231) ``` ### thread -b, 找出当前阻塞其他线程的线程 有时候我们发现应用卡住了， 通常是由于某个线程拿住了某个锁， 并且其他线程都在等待这把锁造成的。 为了排查这类问题， arthas提供了`thread -b`， 一键找出那个罪魁祸首。 `thread -b`{{execute T2}} ```bash $ thread -b "http-bio-8080-exec-4" Id=27 TIMED_WAITING at java.lang.Thread.sleep(Native Method) at test.arthas.TestThreadBlocking.doGet(TestThreadBlocking.java:22) - locked java.lang.Object@725be470 <---- but blocks 4 other threads! at javax.servlet.http.HttpServlet.service(HttpServlet.java:624) at javax.servlet.http.HttpServlet.service(HttpServlet.java:731) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at test.filter.TestDurexFilter.doFilter(TestDurexFilter.java:46) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505) at com.taobao.tomcat.valves.ContextLoadFilterValve$FilterChainAdapter.doFilter(ContextLoadFilterValve.java:191) at com.taobao.eagleeye.EagleEyeFilter.doFilter(EagleEyeFilter.java:81) at com.taobao.tomcat.valves.ContextLoadFilterValve.invoke(ContextLoadFilterValve.java:150) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:429) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318) - locked org.apache.tomcat.util.net.SocketWrapper@7127ee12 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) Number of locked synchronizers = 1 - java.util.concurrent.ThreadPoolExecutor$Worker@31a6493e ``` **注意**， 目前只支持找出synchronized关键字阻塞住的线程， 如果是`java.util.concurrent.Lock`， 目前还不支持。 ### thread -i, 指定采样时间间隔 `thread -n 3 -i 5000`{{execute T2}} ```bash $ thread -n 3 -i 1000 "as-command-execute-daemon" Id=4759 cpuUsage=23% RUNNABLE at sun.management.ThreadImpl.dumpThreads0(Native Method) at sun.management.ThreadImpl.getThreadInfo(ThreadImpl.java:440) at com.taobao.arthas.core.command.monitor200.ThreadCommand.processTopBusyThreads(ThreadCommand.java:133) at com.taobao.arthas.core.command.monitor200.ThreadCommand.process(ThreadCommand.java:79) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.process(AnnotatedCommandImpl.java:96) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.access$100(AnnotatedCommandImpl.java:27) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:125) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:122) at com.taobao.arthas.core.shell.system.impl.ProcessImpl$CommandProcessTask.run(ProcessImpl.java:332) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:756) Number of locked synchronizers = 1 - java.util.concurrent.ThreadPoolExecutor$Worker@546aeec1 ... ``` ### thread –state ，查看指定状态的线程 `thread --state WAITING`{{execute T2}} ```bash [arthas@28114]$ thread --state WAITING Threads Total: 15, NEW: 0, RUNNABLE: 7, BLOCKED: 0, WAITING: 5, TIMED_WAITING: 3, TERMINATED: 0 ID NAME GROUP PRIORITY STATE %CPU TIME INTERRU DAEMON 198 AsyncAppender-Worker-arth system 9 WAITING 0 0:0 false true 3 Finalizer system 8 WAITING 0 0:0 false true 14 RMI Scheduler(0) system 9 WAITING 0 0:0 false true 2 Reference Handler system 10 WAITING 0 0:0 false true 204 pool-8-thread-1 system 5 WAITING 0 0:0 false false ```