Profiling the execution in the VM

[Xerxes Rånby]

Mario Mendez-Lojo skrev:
> Hi guys,
>
> First of all, this is a generic question so please redirect me to the 
> right list (I just couldn't find one) if you consider my post off-topic.
>
> Our project requires of detailed profiling (memory, cpu) of a set of 
> Java applications. The information we get out of -Xprof is not enough. 
> We have been using JProfiler, and are quite happy with it. But we 
> wonder if there is a better, or at least open source, alternative. Can 
> you recommend any other good profiler?
>
> Thank you very much,
> Mario Mendez-Lojo
> postdoc,
> ICES dpt, UT Austin, TX
Four free software profiling alternatives pops into my mind that might 
solve your needs:

VisualVM
https://visualvm.dev.java.net/
VisualVM are quite good for regular java (cpu, memory, threads) program 
profiling it can attach to already running JVM's and are a breeze to 
use. This are the same profiler used in NetBeans.

OProfile
http://oprofile.sourceforge.net
If you want a system wide profiler then use oprofile. It can display 
detailed information of the JVM, system library and the kernel calls 
without having to modify the JVM in any special way.

If you want even more detail of what the JVM are doing then you can use 
gprof (part of gnu binutils) or systemtap, both requires that the JVM 
are modified in order to insert the profiling hooks.

Gprof
http://sourceware.org/binutils/docs-2.19/gprof/index.html (part of gnu 
binutils)
http://mail.openjdk.java.net/pipermail/zero-dev/2009-February/000028.html 
- example of information gathered with gprof

Systemtap
http://sourceware.org/systemtap/
Systemtap hooks can easily be inserted into the OpenJDK hotspot by 
building it using the Icedtea infrastructure and adding 
--enable-systemtap to icedtea's configure.
http://blog.fuseyism.com/index.php/2009/06/01/icedtea-110-released/
http://icedtea.classpath.org/wiki/Main_Page

Cheers
Xerxes