java 无法获得线程转储？任何想法为什么我的应用程序被阻止？

Unable to get thread dump? Any ideas why my app blocks?

提问by James

I have a basic java server app that has 100 worker threads that do simple HEAD requests on urls. I'm using HttpClient 4.x for this.

我有一个基本的 java 服务器应用程序，它有 100 个工作线程，可以对 url 执行简单的 HEAD 请求。我为此使用 HttpClient 4.x。

A few minutes into the run my program just freezes for a couple minutes and I cannot figure out why. Check out the screen shot of what visual vm monitor reports. You can see it flatline. During this time I'm unable to get a good thread dump and visual vm just freezes until it's unblocked. Does anyone have any ideas on what I can do to try and start debugging this guy?

运行几分钟后，我的程序就冻结了几分钟，我不知道为什么。查看visual vm monitor报告的屏幕截图。你可以看到它是扁平的。在这段时间里，我无法获得良好的线程转储，并且可视化虚拟机只是冻结，直到它被解除阻塞。有没有人对我可以做些什么来尝试开始调试这个人有任何想法？

Visual VM: http://tinypic.com/view.php?pic=2i915bs&s=7

可视化虚拟机：http: //tinypic.com/view.php?pic=2i915bs&s=7

Here is the output when I tried to take a jstack dump while it was frozen:

这是我在冻结时尝试进行 jstack 转储时的输出：

jstack -F 4325 
Attaching to process ID 4325, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 16.3-b01
Deadlock Detection:

No deadlocks found.

Thread 4557: (state = BLOCKED)
Error occurred during stack walking:
sun.jvm.hotspot.debugger.DebuggerException: sun.jvm.hotspot.debugger.DebuggerException: get_thread_regs failed for a lwp
    at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$LinuxDebuggerLocalWorkerThread.execute(LinuxDebuggerLocal.java:152)
    at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.getThreadIntegerRegisterSet(LinuxDebuggerLocal.java:466)
    at sun.jvm.hotspot.debugger.linux.LinuxThread.getContext(LinuxThread.java:65)
    at sun.jvm.hotspot.runtime.linux_amd64.LinuxAMD64JavaThreadPDAccess.getCurrentFrameGuess(LinuxAMD64JavaThreadPDAccess.java:92)
    at sun.jvm.hotspot.runtime.JavaThread.getCurrentFrameGuess(JavaThread.java:256)
    at sun.jvm.hotspot.runtime.JavaThread.getLastJavaVFrameDbg(JavaThread.java:218)
    at sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:76)
    at sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:45)
    at sun.jvm.hotspot.tools.JStack.run(JStack.java:60)
    at sun.jvm.hotspot.tools.Tool.start(Tool.java:221)
    at sun.jvm.hotspot.tools.JStack.main(JStack.java:86)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at sun.tools.jstack.JStack.runJStackTool(JStack.java:118)
    at sun.tools.jstack.JStack.main(JStack.java:84)
Caused by: sun.jvm.hotspot.debugger.DebuggerException: get_thread_regs failed for a lwp
    at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.getThreadIntegerRegisterSet0(Native Method)
    at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.access0(LinuxDebuggerLocal.java:51)
    at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocalGetThreadIntegerRegisterSetTask.doit(LinuxDebuggerLocal.java:460)
    at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$LinuxDebuggerLocalWorkerThread.run(LinuxDebuggerLocal.java:127)

回答by Pascal Thivent

I've seen several bug reports about jstackon Linux with a similar trace:

我jstack在 Linux 上看到了几个关于类似跟踪的错误报告：

• JVM Bug Id: 6494722(is supposed to be fixed)
• Ubuntu Bug #597098(this one is not)

• JVM错误 ID：6494722（应该是固定的）
• Ubuntu Bug #597098（这个不是）

Do you get the same result with a kill -3 <pid>?

你得到相同的结果kill -3 <pid>吗？

回答by Daniel Lubarov

What worked for me was running jstack as the process owner without-F.

对我有用的是在没有-F.

回答by bwawok

Very likley due to too much memory usage causing GC. Add the params to java:

很可能是由于内存使用过多导致 GC。将参数添加到java：

-verbosegc -XX:+PrintGCDetails

And see if you notice anything obvious in the output/logs

看看你是否在输出/日志中发现任何明显的东西