Proper usage of -XX:+PrintIdeal (xpost from hotspot-dev)
manojo10386 at gmail.com
Fri Nov 25 02:08:45 PST 2011
I posted this topic on hotspot-dev, but I was advised to post this here as
I am new to using the debug features of hotspot, and was interested in
checking out the graph of a program that I wrote. The program contains a
method 'methodA' which I would like to inspect in terms of optimizations
performed. I verified using the PrintCompilation (and PrintAssembly) flag
that it was indeed JIT compiled. (20.0-b17 of the fastdebug build)
When I use the PrintIdeal flags, however, my output xml files do not
contain any mention of this method. Here is the command I use :
$JAVA_HOME/bin/java -verbose:gc -server -d64 -XX:+UseCompressedOops
-XX:PrintIdealGraphFile="file.xml" -XX:+PrintIdeal $JAVA_OPTS "$@"
I have two output files, file.xml and file1.xml, and neither contain the
method I am looking for. I only have details for 4 methods, one of them
being a decodeArrayLoop and the others being methods from the API (file
input and string manipulation methods). Is it possible that methodA would
not be JIT compiled following the extra instrumentation overhead?
Thanks a lot for your help,
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