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

[Maynard Johnson]

On 11/14/2014 05:09 PM, Volker Simonis wrote:
> 
> 
> On Friday, November 14, 2014, Vladimir Kozlov <vladimir.kozlov at oracle.com <mailto:vladimir.kozlov at oracle.com>> wrote:
> 
>     Volker or Goetz, can you help Maynard to create bugs and prepare webrevs on cr.openjdk for these 3 changes?
> 
> 
> I will create the bugs and have look at the changes on monday.
> 
> Regards,
> Volker
>  
> 
>     Thanks,
>     Vladimir
> 
>     On 11/14/14 10:09 AM, 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.
Sorry, I neglected to mention a third issue:
             3) The mixed mode option for jstack does not work.  Still investigating.

-Maynard
       
> 
>         ---------
> 
>         Any help offered on these two open issues would be greatly appreciated.
> 
>         -Maynard
>