I've got a java application on a windows machine which pins the CPU from time to time. Would like to run a utility to get an idea of how many threads etc that application is creating. Is there such a utility?
jconsole is included with the jdk and includes thread/memory/cpu monitoring
You could try jstack, should be part of the jdk.
I've always been partial to YourKit.
There are lots of others though, both open source and commercial. If you do a google search for "java profilers" you should be able to find one to your liking.
get a look at jvisualvm (in the jdk)
Related
I need a Java way to find a running OS process from which I know to name and path of the executable. I want to look whether it is running right now and I need a way to kill the process if I found it.
My Question is a similar to how-to-find-and-kill-running-win-processes-from-within-java but not restricted to windows.
Am I forced to do an implementation per platform or is there some trick/library/api I'm missing that can do this?
The SIGAR library has some pretty cool support for stuff like this. It has java APIs for listing and killing system processes.
I am running a Java code in a server (remotely) by using javac. Now, I want to perform memory profiling remotely because as YourKit say's,
Picked up JAVA_TOOL_OPTIONS:
Cannot start the profiler UI: display is not available on this machine.
Can anybody help me how can I do this easily.
If your server starts with YourKit profiler agent (according to the output) you just need to start YourKit profiler UI and connect it to the remote profiler agent. There is "Monitor Remote Applications" on profiler start screen
Here is the direct links to YourKit help:
http://www.yourkit.com/docs/11/help/profiling_j2ee_remote.jsp
I would recommend you to use JProfiler.You can get it from here and found many helpful tutorials.Here is JProfiler manual
This is exact what is happening in our pre-production env...
actually if you want to launch the YourkitUI on remote machine directly, the way I am currently doing it is using Xmanager->xshell http://www.netsarang.com/products/xmg_overview.html
You also need to install X-server as precondition. You will be able to run any kind of UI remotely, not only yourkit.
also make sure your yourkit launch conf like this
-agentpath:$YOURKIT_HOME/bin/linux-x86-64/libyjpagent.so=disablestacktelemetry,
disableexceptiontelemetry,builtinprobes=none,delay=20000,sessionname=jboss-pre-prod
your kit remote profiling
if this helps you. If this process is not helping may be we can think of any other option.
I am using eclipse to write java code. If I'm debugging some code I can set a breakpoint and follow along as the code goes through each of the functions or I can backtrack. I can also look at the call hierarchy or the references to get an idea. But that's not enough.
I would like to have a some sort of time-based visualization of what each thread is doing along the process from ... let's say "point A" (pressing a button on the interface) to "point B" (getting the result). I want to see which classes/methods were called in what order. I want a good way to visualize what kind of output is coming from one method and going into another method which fires off a new process ...etc.
Is a profiler the only thing available for this type of visualization? Basically I want an action diagram or flow diagram created. Is there some plugin or app which can generate something like this?
Edit: Here is an example of what I'm thinking ... at least visually:
essmodel.sourceforge.net/index.html
It has some flow of where the code is leading. But I think this is just a static map of what classes lead to other classes and what inputs/output options are available. I would want to map the flow based on a specific case.
JProfiler offers such a view, it's called the "Call tracer":
It's important to restrict your filters very carefully in order not to record to much data.
Disclaimer: My company develops JProfiler.
I believe using a profiler is going to be your best option. Are you familiar with VisualVM? It comes with the JDK (look for "jvisualvm.exe" inside your JDK's bin directory) and is capable of profiling local virtual machines automatically as well as remote machines when configured properly. And it does give a pretty slick overview of what threads are running and the code they are spending time in, so I think you could easily do what you need from it. And best of all, it's free :)
As I said, local profiling is a breeze. You just run JVisualVM.exe standalone, and it will find any and all java processes running on the local machine automatically (you can just pick them out of a menu that VisualVM gives you upfront). If you want to profile remotely, set the following VM arguments for whatever it is that you're running:
-Dcom.sun.management.jmxremote.port=[0-65535]
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false
Then within VisualVM, use the hostname of the machine your remote JVM is running on and the port you configured in the first VM argument above.
I've looked through couple of articles here such as:
java stack dump on windows
Thread dump programmatically /JDI (Java Debugger Interface)
But didnt catch the exact answer.
The problem:
There is a Java5 Application on Windows that's runs as a service (so we dont have a console where we are able to use Ctrl+Break for Dumping).
And sometimes Application hangs and we need a thread dump.
We've tried "jstack" but it doesnt work in our env (we found out that its Java6 only compatible).
So we made a C++ app that calls thread dump via .dll call method attaching to the Java app process, and because of this it needs Local Admin rights, that is not so good.
So we'd like other options that works without admin rights and works with Java 5 without lots of rework of existing code.
Method with Printing in LOOP thread dumps (Thread.getAllStackTraces()) is not an option because we need to refactor lots of applications in order to make it work.
So that just an util that works from "outside" of applications would be a best option.
Thanks in advance!
One option is to dump all the information using jmap, and then analyzing it using other tool.
jmap -dump:format=b,file=<filename>.hprof <jvm_pid>
I am not sure, buy I think it will work on Java 5.
References:
HPjmeter-like graphical tool to view -agentlib:hprof profiling output
You can attach to the process with JConsole to detect deadlocks and get stack traces of the threads. For more information, see here: http://java.sun.com/developer/technicalArticles/J2SE/jconsole.html
What tools are available to view the output of the built-in JVM profiler? For example, I'm starting my JVM with:
-agentlib:hprof=cpu=times,thread=y,cutoff=0,format=a,file=someFile.hprof.txt
This generates output in the hprof ("JAVA PROFILE 1.0.1") format.
I have had success in the past using HPjmeter to view these output files in a reasonable way. However, for whatever reason the files that are generated using the current version of the Sun JVM fail to load in the current version of HPjmeter:
java.lang.NullPointerException
at com.hp.jmeter.f.jb.a(Unknown Source)
at com.hp.jmeter.f.a.a(Unknown Source)
at com.hp.c.a.j.z.run(Unknown Source)
Exception in thread "HPeprofDataFileReaderThread" java.lang.AssertionError: null pointer exception from loader
at com.hp.jmeter.f.a.a(Unknown Source)
at com.hp.c.a.j.z.run(Unknown Source)
(Why would they obfuscate the bytecode for a free product?!)
Two questions arise from this:
Does anyone know the cause of this HPjmeter error? (EDIT: Yes--see below)
What other tools exist to read hprof files? And why are there none from Sun (are there)?
I know the Eclipse TPTP and other tools can monitor JVMTI data on the fly, but I need a solution that can process the generated hprof files after the fact since the deployed machine only has a JRE (not a JDK) intalled.
EDIT: A very helpful HPjmeter developer replied to my question on an HP ITRC forum indicating that heap=dump needs to be included in the -agentlib options temporarily until a bug in HPjmeter is fixed. This information makes HPjmeter viable again, but I will still leave the question open to see if anyone knows of any other tools.
EDIT: As of version 4.0.00 of HPjmeter (available 05/2009) this bug has been fixed.
Your Kit Java Profiler is able to read hprof snapshots (I am not sure if only for memory profiling or for CPU as well). It is not free but is by far the best java profiler I ever used. It presents the results in a clear, intuitive way and performs well on large data sets. The documentation is also pretty good.
For viewing and analyzing the output of hprof=samples or hprof=cpu I have used PerfAnal with good results. The GUI is a bit spartan, but very useful.
PerfAnal is a free download (GPL, originally an example project in the book Java Programming on Linux).
See this article:
http://www.oracle.com/technetwork/articles/javase/perfanal-137231.html
for more information and the download.
Normally you can just run
java -jar PerfAnal.jar hprof.java.txt
You may need to fiddle with -Xmx for large hprof files.
I am not 100% sure it'll work (it sounds like it will) and I am not sure it'll show it in the format you want... but have you thought about the VisualVM?
I believe it'll open up the resulting file.
I have been using Eclipse Memory Analyzer for analyzing different performance problems successfully. First of all, install the tool as described in the project webpage in Eclipse.
After that, you can create a dump file knowing the pid of the jvm to be analyzed
jmap -dump:format=b,file=<filename>.hprof <jvm_pid>
Then just import the .hprof file in eclipse. It has some automatic reports that try (for me they usually do not work) to point out which could be the possible problems.
Edit:
Answering the comment: You are right, it is more like a leak finder for Java. For performance problems, I have played with JRat for small projects. It shows time comsumed per method, number of times a method is called, hierarchy of calls, etc. The only problem is that as far as I know, it does not support .hprof files. To use it, yo need to execute your program adding a VM argument
-javaagent:<path>/shiftone-jrat.jar
This will generate a directory with the profile captured by the tool. Then, execute
java -jar shiftone-jrat.jar
And open the trace. Even been a simple tool, I think it could be useful.