### 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 "C1 CompilerThread0" [Internal] cpuUsage=1.63% deltaTime=3ms time=1170ms "arthas-command-execute" Id=23 cpuUsage=0.11% deltaTime=0ms time=401ms RUNNABLE at java.management@11.0.7/sun.management.ThreadImpl.dumpThreads0(Native Method) at java.management@11.0.7/sun.management.ThreadImpl.getThreadInfo(ThreadImpl.java:466) at com.taobao.arthas.core.command.monitor200.ThreadCommand.processTopBusyThreads(ThreadCommand.java:199) at com.taobao.arthas.core.command.monitor200.ThreadCommand.process(ThreadCommand.java:122) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.process(AnnotatedCommandImpl.java:82) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.access$100(AnnotatedCommandImpl.java:18) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:111) at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:108) at com.taobao.arthas.core.shell.system.impl.ProcessImpl$CommandProcessTask.run(ProcessImpl.java:385) at java.base@11.0.7/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) at java.base@11.0.7/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base@11.0.7/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) at java.base@11.0.7/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base@11.0.7/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base@11.0.7/java.lang.Thread.run(Thread.java:834) "VM Periodic Task Thread" [Internal] cpuUsage=0.07% deltaTime=0ms time=584ms ``` * 没有线程ID，包含`[Internal]`表示为JVM内部线程，参考`dashboard`命令的介绍。 * `cpuUsage`为采样间隔时间内线程的CPU使用率，与`dashboard`命令的数据一致。 * `deltaTime`为采样间隔时间内线程的增量CPU时间，小于1ms时被取整显示为0ms。 * `time` 线程运行总CPU时间。 注意：线程栈为第二采样结束时获取，不能表明采样间隔时间内该线程都是在处理相同的任务。建议间隔时间不要太长，可能间隔时间越大越不准确。 可以根据具体情况尝试指定不同的间隔时间，观察输出结果。 ### 当没有参数时，显示第一页线程信息 默认按照CPU增量时间降序排列，只显示第一页数据，避免滚屏。 `thread`{{execute T2}} ```bash $ thread Threads Total: 33, NEW: 0, RUNNABLE: 9, BLOCKED: 0, WAITING: 3, TIMED_WAITING: 4, TERMINATED: 0, Internal threads: 17 ID NAME GROUP PRIORITY STATE %CPU DELTA_TIME TIME INTERRUPT DAEMON -1 C2 CompilerThread0 - -1 - 5.06 0.010 0:0.973 false true -1 C1 CompilerThread0 - -1 - 0.95 0.001 0:0.603 false true 23 arthas-command-execute system 5 RUNNABLE 0.17 0.000 0:0.226 false true -1 VM Periodic Task Thread - -1 - 0.05 0.000 0:0.094 false true -1 Sweeper thread - -1 - 0.04 0.000 0:0.011 false true -1 G1 Young RemSet Sampling - -1 - 0.02 0.000 0:0.025 false true 12 Attach Listener system 9 RUNNABLE 0.0 0.000 0:0.022 false true 11 Common-Cleaner InnocuousThrea 8 TIMED_WAI 0.0 0.000 0:0.000 false true 3 Finalizer system 8 WAITING 0.0 0.000 0:0.000 false true 2 Reference Handler system 10 RUNNABLE 0.0 0.000 0:0.000 false true 4 Signal Dispatcher system 9 RUNNABLE 0.0 0.000 0:0.000 false true 15 arthas-NettyHttpTelnetBootstra system 5 RUNNABLE 0.0 0.000 0:0.029 false true 22 arthas-NettyHttpTelnetBootstra system 5 RUNNABLE 0.0 0.000 0:0.196 false true 24 arthas-NettyHttpTelnetBootstra system 5 RUNNABLE 0.0 0.000 0:0.038 false true 16 arthas-NettyWebsocketTtyBootst system 5 RUNNABLE 0.0 0.000 0:0.001 false true 17 arthas-NettyWebsocketTtyBootst system 5 RUNNABLE 0.0 0.000 0:0.001 false true ``` ### thread --all, 显示所有匹配的线程 显示所有匹配线程信息，有时需要获取全部JVM的线程数据进行分析。 `thread --all`{{execute T2}} ### 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 -i 1000` : 统计最近1000ms内的线程CPU时间。 `thread -i 1000`{{execute T2}} * `thread -n 3 -i 1000` : 列出1000ms内最忙的3个线程栈 `thread -n 3 -i 1000`{{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: 16, NEW: 0, RUNNABLE: 9, BLOCKED: 0, WAITING: 3, TIMED_WAITING: 4, TERMINATED: 0 ID NAME GROUP PRIORITY STATE %CPU DELTA_TIME TIME INTERRUPTE DAEMON 3 Finalizer system 8 WAITING 0.0 0.000 0:0.000 false true 20 arthas-UserStat system 9 WAITING 0.0 0.000 0:0.001 false true 14 arthas-timer system 9 WAITING 0.0 0.000 0:0.000 false true ```