RFR: 8276265: jcmd man page is outdated

[David Holmes]

On Wed, 10 Nov 2021 06:44:17 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> It was noticed that a number of updates to the jcmd subcommands (some new, some modified) had not been added to the manpage. The text was supplied by @tstuefe - thanks Thomas. I applied the changes to the closed markdown sources and regenerated the nroff file. For easier review I have generated a html version that can be viewed here:
>> 
>> https://htmlpreview.github.io/https://github.com/dholmes-ora/jdk/blob/57c00815460ffef201239eafac322b4dd246da1b/jcmd.html
>> 
>> Summary of changes:
>> 
>> New Commands:
>> - Compiler.perfmap
>> - System.trim_native_heap
>> - VM.cds
>> - VM.classloaders
>> - VM.events
>> - VM.metaspace
>> 
>> Missing flags:
>> - GC.class_histogram -parallel
>> - GC.heap_dump - gz and overwrite options
>> - Thread.print -e
>> 
>> There are further improvements that could be made, some mentioned in the bug report. I also noticed a general confusion between arguments and options with some subcommands, but I did not try to address that.
>> 
>> Thanks,
>> David
>
>> It was noticed that a number of updates to the jcmd subcommands (some new, some modified) had not been added to the manpage. The text was supplied by @tstuefe - thanks Thomas. I applied the changes to the closed markdown sources and regenerated the nroff file. For easier review I have generated a html version that can be viewed here:
> 
> Your link did not work, I generated them and put them here for reviewer convenience: https://gist.github.com/tstuefe/8bd16a64061537d23e9ee556c7bd2965
> 
> Looks good. Most of the commands are ours (SAPs), but I had no idea that man pages existed.
> 
>> 
>> There are further improvements that could be made, some mentioned in the bug report. I also noticed a general confusion between arguments and options with some subcommands, but I did not try to address that.
>> 
> 
> jcmd commands in general feel a bit anarchic. Different styles etc. But I fear that cannot be changed because of backward compatibility.
> 
> Thanks, Thomas

Thanks for the reviews @tstuefe  and @plummercj !

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PR: https://git.openjdk.java.net/jdk/pull/6271