Re: Release Candidate 2 for OProfile 0.9.4

[Maynard J. <may...@us...>]

William Cohen wrote:
> Maynard Johnson wrote:
>   
>> William Cohen wrote:
>>     
>>> Maynard Johnson wrote:
>>>   
>>>       
>>>> William Cohen wrote:
>>>>     
>>>>         
>>>   
>>>       
>>>>> What happens when someone has multiple JITs on the machine and 
>>>>> oprofile is configured for a particular one? Oprofile is always going 
>>>>> to use the one used for the build? Might be an issue if someone puts 
>>>>> in a newer version on the machine and oprofile isn't rebuilt.
>>>>>       
>>>>>           
>>>> The Java agent libraries support a particular API.  So, if you specify a 
>>>> JDK version 1.5 via the '--with-java' configure option, both JVMPI and 
>>>> JVMTI agent libraries are built.  (JVMPI was deprecated in Java 1.5 and 
>>>> removed in 1.6.) During profiling, you can use any JVM version that 
>>>> supports the API of the agent library, as long as that JVM is the same 
>>>> bitness as the agent library.  On bi-arch machines, there may be both 
>>>> bitness versions of the JVM that can be installed by the user.  So it 
>>>> would be recommended to build oprofile both ways (e.g., 32-bit and 
>>>> 64-bit).  This is another reason for putting the libopagent and the Java 
>>>> agent libraries in a separate package, since it's only the libraries 
>>>> (which are used by the JVM) that need both bitness versions.  (I think 
>>>> that's another tip I should put in the README_PACKAGERS file.)
>>>>
>>>> Thanks!
>>>>
>>>> -Maynard
>>>>     
>>>>         
>>>>> -Will
>>>>>       
>>>>>           
>>> Hi Maynard,
>>>
>>> Been looking at the OProfile spec file a bit more. Only found jvmti.h for fedora 
>>> 9 this in java-1.6.0-openjdk-devel. I looked for jvmpi.h; couldn't find 
>>> anything. Not surprising given there doesn't appear to be a java-1.5.0 based 
>>>   
>>>       
>> Yes, that's as expected.
>>     
>>> version. Are all the jvm interoperable for jvmti.h and jvmpi.h? Trying to figure 
>>> out if the resulting oprofile is going to work for all 1.6-based jvms, or just 
>>> the one the oprofile is built against.
>>>   
>>>       
>> JVMTI agent library can be used with any JVM 1.5 or greater.  The caveat
>> is that if the JVM is, say, 64-bit, then the must be a 64-bit JVMTI
>> agent library availalble.  Likewise, if the JVM is 32-bit, then a 32-bit
>> JVMTI agent lib is needed.  That's why I mentioned above that for
>> bi-arch systems, the packager would probably want to package the
>> libopagent and agent libraries (libjvm[t | p]i_oprofile) in a separate
>> package and build twice -- once as 32-bit and a second time as 64-bit.
>>     
>>> With the shared libraries I would think that an entry would be needed for 
>>> /etc/ld.conf.d and /sbin/ldconfig would need to be run in %post %postun.
>>>   
>>>       
>> I don't have any real-life experience in packaging rpms, so I hadn't
>> thought about this.  Good catch.  That's another tip to add to the
>> README_PACKAGERS file.  :-)
>>     
>>> Did you verify that the shared library from the rpm was the one being used when 
>>> testing things out? It could be possible that another copy elsewhere on the 
>>> machine was being used.
>>>   
>>>       
>> I was just manually setting the session's LD_LIBRARY_PATH.
>>
>> -Maynard
>>     
>>> -Will
>>>       
>
> Hi Maynard,
>
> I took another pass at generating the rpm based on oprofile 0.9.4rc2. I put some 
> stuff to avoid people having to manually set LD_LIBRARY_PATH. The current 
> version of the source rpm is at:
>
> http://people.redhat.com/wcohen/oprofile-0.9.4rc2-7.fc9.src.rpm
>
> This may be a silly question, but how does one get profiling data on a java 
> program using a jit? There doesn't seems to be a manpage for /usr/bin/opjitconv. 
> Are there instructions some where for profiling java/jit programs?
>   
Not a silly question at all.  Actually, opjitconv is not a user-runnable
program, so that's why there's no man page.  The doc/oprofile.html file
has some new and updated sections on building/installing/profiling with
the new JIT support.  Additionally, there's a new manual
(doc/op-jit-devel.html) that describes how third parties can leverage
the JIT support to build agent libraries for other JIT virtual
machines.  Both of these HTMLs are in the oprofile-0.9.4-rc2 tar ball.

Regards,
-Maynard
> -Will
>
>