[PATCH RFC 0/2] Add linux/ppc64 support for Hotspot serviceability agent to read core files

[Dmitry Samersoff]

Maynard,

Thank you for this contribution.

Could I ask you to prepare a webrev?

http://openjdk.java.net/guide/webrevHelp.html

-Dmitry


On 2014-11-14 21:09, Maynard Johnson wrote:
> When Hotspot SA tools jmap, jstack, and jsadebugd are run against a core file, they fail with the following runtime exception:
> 
>      OS/CPU combination linux/ppc64 not yet supported
> 
> I will post a patch set that adds this support.  The patch set consists of the following patches:
> 
> PATCH 1/2: Updates to non-Java files to support linux/ppc64 Hotspot SA with core files
> 
> PATCH 2/2: New PPC64 class files (and updates to generic files) to support linux/ppc64 Hotspot SA with core files
> 
> These two patches apply cleanly to a November 13 pull of the jdk9-dev upstream sources.
> 
> ------------
> Open issues:
> ------------
>   1) The jstack tool does not print a stack entry for the 'main()' method of the Java
>      workload (attached) under test.  For example:
> 
>      (Note:  Addresses and method signatures elided for brevity.)
> 
>        Thread 24358: (state = IN_JAVA, current Java SP = null
>        )
>         - java.lang.String.getChars(...) @bci=58, line=814, pc=..., Method*=... (Compiled frame; ... imprecise)
>         - test.run_test() @bci=80, line=33, pc=..., Method*=... (Compiled frame)
>      ==> (Expect an entry for test.main() here)
>      
>   2) The jstack tool sometimes prints what appears to be two complete stacks for the Java workload. For example:
> 
>        Thread 24779: (state = IN_JAVA, current Java SP = null
>        )
>         - java.lang.String.getChars(...) @bci=58, line=814, pc=..., Method*=... (Compiled frame; ... imprecise)
>         - test.run_test() @bci=80, line=33, pc=..., Method*=... (Compiled frame)
>         - test.get_my_chars(...) @bci=39, line=15, pc=..., Method*=... (Compiled frame)
>         - test.run_test() @bci=92, line=34, pc=..., Method*=... (Compiled frame)
> 
>        Again, the 'test.main' method is missing, but there's also the anomaly of the 
>        test.run_test' method showing up twice in the stack, implying that it is called
>        by 'test.get_my_chars' at line 15.  But that that is not accurate. In fact, run_test
>        does call String.getChars at line 33 *and* it calls test.get_my_chars at line 34 --
>        but these are totally distinct call graphs.  Somehow, we are seeing these two distinct
>        stacks in the core file, which seems impossible.
> 
> ---------
> 
> Any help offered on these two open issues would be greatly appreciated.
> 
> -Maynard
> 


-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.