Build 449 and GCC 2.9 support

matiasm · Post by **matiasm** » Tue Nov 23, 2004 8:41 am

Hi! I've been trying to get YourKit build 449 to work on Red Hat Enterprise Linux ES release 3. The dependencies are fine when using the GCC2.9 plugin:

libltdl.so.3 => /usr/lib/libltdl.so.3 (0x4004f000)
libstdc++-libc6.2-2.so.3 => /usr/lib/libstdc++-libc6.2-2.so.3 (0x40057000)
libc.so.6 => /lib/i686/libc.so.6 (0x40099000)
libdl.so.2 => /lib/libdl.so.2 (0x401d3000)
libm.so.6 => /lib/i686/libm.so.6 (0x401d6000)
libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x401f8000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x80000000)

Somehow profiling just won't start. The JVM loads the plugin but it just doesn't log anything. I can profile the same application on Win32 with the same setup. Here's output from my JVM:
[x@y]$ java -version
java version "1.4.2_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_04-b05)
Java HotSpot(TM) Client VM (build 1.4.2_04-b05, mixed mode)

[x@y]$ java -Xrunyjpagent:help
YourKit Java Profiler 3.1.1 #449 agent usage: -Xrunyjpagent[:help]|[:<option>, ...]

Any hints to get the plugin work? Unfortunately the solution is not to upgrade a newer system :)

Post by **Vladimir Kondratyev** » Tue Nov 23, 2004 6:36 pm

Somehow profiling just won't start. The JVM loads the plugin but it just doesn't log anything.

1. What is the command line you are using to launch JVM with profiler agent?

2. What is the JVM output produced by this command line?[/quote]

matiasm · Post by **matiasm** » Tue Nov 23, 2004 8:27 pm

1. What is the command line you are using to launch JVM with profiler agent?

I'm using the startup script that comes with Tomcat. I have appended the following to CATALINA_OPTS
-Djava.awt.headless=true -Xrunyjpagent:onexit=memory,dir=/home/matiasm/debug
If I look process listing the parameter seems to go to JVM as it should.

matiasm 27560 1 0 23:09 pts/0 00:00:03 /www/javakehitys/j2sdk1.4.2_04/bin/java -Xms64m -Xmx64m -Djava.awt.headless=true -Xrunyjpagent onexit=memory,dir=/home/matiasm/debug -Djava.endorsed.dirs=/www/javakehitys/tomcat/common/endorsed -classpath /www/javakehitys/j2sdk1.4.2_04/lib/tools.jar:/www/javakehitys/tomca

2. What is the JVM output produced by this command line?

From catalina.out I found
[YourKit Java Profiler 3.1.1 #449] Listening on port 10000...

And it is really listening
[x@y logs]$ netstat -lnp|grep 10000
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 **:10000 0.0.0.0:* LISTEN 27560/java

The mysterious thing is that the plugin just won't write any output to the debug directory. File permissions should be ok.

Post by **Vladimir Kondratyev** » Wed Nov 24, 2004 7:36 am

Please try to launch very simple sample application from $YJP_HOME/samples/sample2 directory. It should create memory snapshot in your home directory.

If everything works, then I see only one possible problem:

You are using onexit=memory option and Tomcat server is not properly shutted down (perhaps kill -9 is used). Have you tried to connect to running Tomcat from profiler UI and capture memory snapshot?

matiasm · Post by **matiasm** » Wed Nov 24, 2004 9:33 am

You are using onexit=memory option and Tomcat server is not properly shutted down (perhaps kill -9 is used). Have you tried to connect to running Tomcat from profiler UI and capture memory snapshot?

That was it. The Tomcat process died too soon and had no time to write any debug output.

The situation I'm trying to figure out is a little bit trickier. Does the onexit option work if JVM crashes? It's a bit awkward if I must poll the server constantly before the crash happens.

Thank you for your help!

Post by **Anton Katilin** » Wed Nov 24, 2004 10:28 am

If Java program crashes, then onexit should work. If JVM itself crashes inside its native code, then JVM exits immediately, and no callbacks are executed.

What kind of crashes do you experience? What messages are printed in console when crash happens?

matiasm · Post by **matiasm** » Wed Nov 24, 2004 10:43 am

Actually the Java application doesn't crash. The application I'm debugging is known to leak memory. Eventually JVM runs out of memory and crashes (the Java application tries to allocate more and more memory but it can't because the heap is full). I'll try to get a log file for you when JVM crashes again.