RFR: 8146948: Add help information to log tags

[Robbin Ehn]

Hi Marcus,

Looks good, thanks for fixing!

/Robbin

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
>