RFE: Add compressed oops to VM info string

[Volker Simonis]

+1 from me

On Thu, Nov 10, 2011 at 12:44 PM, Christian Thalinger
<christian.thalinger at oracle.com> wrote:
>
> On Nov 10, 2011, at 12:16 PM, Volker Simonis wrote:
>
>> Hi Kris,
>>
>> first I want to say that I like and support your enhancement request.
>>
>> However once we do this, if would suggest printing other information as well.
>> Particularly the fact if we're using tiered compilation comes to my mind here.
>>
>> I would therefore suggest to use a less verbose "compressed oops"
>> string and also
>> print the concrete compressed oops mode that's  actually used
>> (unscaled, zerobased, heapbased).
>> This information may be particularly usefull because it may change
>> depending on the users heap setting
>> and  the current system memory situation.
>>
>> So finally, we could use something like:
>>
>> OpenJDK 64-Bit Server VM (build 20.0-b11-internal, mixed mode, tiered,
>> compr-oops=unscaled)
>
> Honestly I don't know what it takes to change that string since it's a public known option.  But my personal opinion is:  print the most important runtime settings like JIT mode, GC used, compressed oops mode.  Something along these lines:
>
> Java HotSpot(TM) Server VM (build 23.0-b03, mixed mode, tiered, serial gc, zerobased coops)
>
> Just my two cents...
>
> -- Chris
>
>>
>> For such a version string, it would be probably better to construct
>> the string on the fly, otherwise
>> the 'info_strs' struct you are currently using may become too big.
>>
>> What are your opinions?
>>
>> Regards,
>> Volker
>>
>>
>> On Thu, Nov 10, 2011 at 8:54 AM, Krystal Mok <rednaxelafx at gmail.com> wrote:
>>> Hi all,
>>> I'd like to propose to add "compressed oops" to the VM info string, so that
>>> people using "java -version" can get a better understanding of the
>>> ergonomics of the VM.
>>> I've posted a patch [1], against hsx20's master. The files modified are
>>> still pretty much the same on hotspot-main's master.
>>> With the patch applied, "java -version" may show:
>>> OpenJDK 64-Bit Server VM (build 20.0-b11-internal, mixed mode, compressed
>>> oops)
>>> and what used to work still works:
>>> OpenJDK Client VM (build 20.0-b11-internal, mixed mode, sharing)
>>> P.S. Alibaba (Taobao)'s OCA is submitted already, still waiting for approval
>>> from Oracle.
>>> Regards,
>>> Kris Mok
>>> Software Engineer, Taobao (http://www.taobao.com)
>>> [1]: https://gist.github.com/1354299
>
>