RFR: 8146948: Add help information to log tags

[Ioi Lam]

The changes look good to me, but maybe the bug title "Add help 
information to log tags" needs to changed?

When I filed the bug, my main question was "what the heck is ihop", and 
the new output is "you can use ihop with gc+ergo", which doesn't really 
answer my question.

Thanks
- Ioi

On 5/4/16 2:38 AM, Marcus Larsson wrote:
> Hi,
>
> Need a Review for this.
>
> Rebased the webrev to jdk9/hs in place.
>
>
> Thanks,
> Marcus
>
> On 04/14/2016 03:48 PM, Marcus Larsson wrote:
>> Hi,
>>
>> Please review the following patch to add descriptions to logging 
>> tagsets.
>>
>> Summary:
>> Tagsets may now be given a description in 
>> logTagSetDescriptions.inline.hpp. All described tagsets are listed in 
>> the -Xlog:help output as well as in the LogConfiguration::describe 
>> output. The patch also adds trace level logging that lists *all* 
>> tagsets in the VM (-Xlog:logging=trace). The previous 'logging=trace 
>> logging' has been moved to 'logging=debug'.
>>
>> Example log output:
>>
>> ...
>> [0.544s][debug][logging] Described tag combinations:
>> [0.544s][debug][logging]  logging: Logging for the log framework itself
>> ...
>> [0.544s][trace][logging] All available tag sets: arguments, 
>> biasedlocking, classinit, classload, classload+constraints, 
>> classload+preorder, classloaderdata, classpath, classresolve, 
>> classunload, constraints, defaultmethods, ergo, exceptions, gc, 
>> gc+age, gc+alloc, gc+alloc+region, gc+barrier, gc+bot, gc+classhisto, 
>> gc+classhisto+start, gc+compaction, gc+cpu, gc+ergo, gc+ergo+cset, 
>> gc+ergo+heap, gc+ergo+ihop, gc+ergo+refine, gc+freelist, 
>> gc+freelist+census, gc+freelist+stats, gc+heap, gc+heap+coops, 
>> gc+heap+exit, gc+heap+region, gc+humongous, gc+ihop, gc+jni, 
>> gc+liveness, gc+marking, gc+marking+start, gc+metaspace, 
>> gc+metaspace+alloc, gc+metaspace+freelist, gc+phases, 
>> gc+phases+start, gc+phases+task, gc+phases+verify, 
>> gc+phases+verify+start, gc+plab, gc+promotion, gc+ref, gc+ref+start, 
>> gc+refine, gc+region, gc+remset, gc+remset+exit, gc+remset+scrub, 
>> gc+scavenge, gc+start, gc+state, gc+stats, gc+stringdedup, 
>> gc+stringtable, gc+survivor, gc+sweep, gc+task, gc+task+stats, 
>> gc+task+thread, gc+task+time, gc+tlab, gc+verify, gc+verify+start, 
>> gc+workgang, heap+ergo, itables, jfr, jfr+instrumentation, jfr+types, 
>> logging, logging+test, modules, monitorinflation, monitormismatch, 
>> os, os+cpu, os+thread, pagesize, protectiondomain, ref, safepoint, 
>> safepointcleanup, stacktrace, startuptime, verification, vmoperation, 
>> vtables
>>
>>
>> Webrev:
>> http://cr.openjdk.java.net/~mlarsson/8146948/webrev.00/
>>
>> Issue:
>> https://bugs.openjdk.java.net/browse/JDK-8146948
>>
>> Testing:
>> Internal VM tests through RBT
>>
>> Thanks,
>> Marcus
>>
>