RFE: Add compressed oops to VM info string

[Srinivas Ramakrishna]

+1 to David's (and others') suggestion:-

I agree that +PrintFlagsFinal makes this less subjective and more uniform.

-- ramki

On Thu, Nov 10, 2011 at 1:31 PM, David Holmes <david.holmes at oracle.com>wrote:

> In case I didn't mention it earlier there is also -Xinternalversion which
> might be extended this way.
>
> But personally I think printing the flags is the way to go, and if the
> desired flags are not printed then that is a RFE for the print-flags
> options.
>
> David
>
>
> On 11/11/2011 4:02 AM, Mandy Chung wrote:
>
>> FWIW. Kumar added an internal option -XshowSettings to the launcher in
>> JDK 7 to print various VM and java settings. This could be a potential
>> place to include "compressed oops" and other VM ergonomic setting in. It
>> takes an optional suboption "all, vm, properties, locale".
>>
>> $ java -XshowSettings:vm
>>
>> VM settings:
>> Stack Size: 320.00K
>> Max. Heap Size (Estimated): 910.00M
>> Ergonomics Machine Class: server
>> Using VM: Java HotSpot(TM) Server VM
>>
>> [snip..]
>>
>> java -XshowSettings -version doesn't print the additional information. I
>> haven't spent time looking into the reason why.
>>
>> Mandy
>>
>> On 11/10/11 08:01, Paul Hohensee wrote:
>>
>>> I don't think the version string is the place for dumping ergo
>>> decision results,
>>> rather I agree with David Holmes and Joe that PrintFlagsFinal,
>>> PrintCommandLineFlags,
>>> or some other switch should be used. We shouldn't have "mixed mode",
>>> etc. in the
>>> string either, but given that they're there we're kinda stuck with them.
>>>
>>> The reason we have "Server" and "Client" (and "Embedded, btw) is to
>>> distinguish
>>> builds that are statically different. Tiered got folded into Server
>>> awhile ago, which
>>> is why it's no longer mentioned in the version string.
>>>
>>> Changing the version string is a non-trivial thing to do: it has to go
>>> through
>>> an approval process because it's a supported public interface. There
>>> are, e.g.,
>>> quite a few version string parsers out there that wouldn't take kindly
>>> to change.
>>>
>>> Paul
>>>
>>> On 11/10/11 8:18 AM, Volker Simonis wrote:
>>>
>>>> +1 from me
>>>>
>>>> On Thu, Nov 10, 2011 at 12:44 PM, Christian Thalinger
>>>> <christian.thalinger at oracle.**com <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<https://gist.github.com/1354299>
>>>>>>>
>>>>>>
>>>>>
>>
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