view agent/doc/cireplay.html @ 12250:9044964f9163

8024669: Native OOME when allocating after changes to maximum heap supporting Coops sizing on sparcv9 Summary: After changes in 8010722 the ergonomics for calculating the size of the heap that supports zero based compressed oops changed. This lead to the VM actually using zero based compressed oops. Due to low default HeapBaseMinAddress, the OS mapping in the application image at the same address, and limitations of the malloc implementation on Solaris this resulted in very little C heap available for the VM. So the VM immediately gives a native OOME when the machine has lots of physical memory (>=32G). The solution is to increase the HeapBaseMinAddress so that the VM has enough C heap. Reviewed-by: kvn, brutisso
author tschatzl
date Wed, 18 Sep 2013 13:18:52 +0200
parents 7b23cb975cf2
children
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<title>
Replay
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<h1>Compiler replay</h1>
<p>
The compiler replay is a function to repeat the compiling process from a crashed java process in compiled method<br>
This function only exists in debug version of VM
</p>
<h2>Usage</h2>
<pre>
First, use SA to attach to the core file, if succeeded, do
       hsdb&gt; dumpreplaydata &lt;address&gt; | -a | &lt;thread_id&gt; [&gt; replay.txt]
       create file replay.txt, address is address of Method, or nmethod(CodeBlob)
       hsdb&gt; buildreplayjars [all | boot | app]
       create files:
         all:
           app.jar, boot.jar
         boot:
           boot.jar
         app:
           app.jar
       exit SA now.
Second, use the obtained replay text file, replay.txt and jar files, app.jar and boot.jar, using debug version of java
       java -Xbootclasspath/p:boot.jar -cp app.jar -XX:ReplayDataFile=&lt;datafile&gt; -XX:+ReplayCompiles ....
       This will replay the compiling process.

       With ReplayCompiles, the replay will recompile all the methods in app.jar, and in boot.jar to emulate the process in java app.

notes:
       1) Most time, we don't need the boot.jar which is the classes loaded from JDK. It will be only modified when an agent(JVMDI) is running and modifies the classes.
       2) If encounter error as "&lt;flag&gt;" not found, that means the SA is using a VMStructs which is different from the one with corefile. In this case, SA has a utility tool vmstructsdump which is located at agent/src/os/&lt;os&gt;/proc/&lt;os_platform&gt;

       Use this tool to dump VM type library:
       vmstructsdump libjvm.so &gt; &lt;type_name&gt;.db

       set env SA_TYPEDB=&lt;type_name&gt;.db (refer different shell for set envs)