RFR (XS): 8078399: Deprecate -Xoss, -Xsqnopause, -Xoptimize and -Xboundthreads options in JDK 9

David Holmes david.holmes at oracle.com
Wed Jun 24 04:25:20 UTC 2015

Hi Dmitry,

On 23/06/2015 11:02 PM, Dmitry Dmitriev wrote:
> Hello David,
> Please, see my comments inline.
> On 23.06.2015 15:49, David Holmes wrote:
>> Hi Dmitry,
>> On 23/06/2015 8:35 PM, Dmitry Dmitriev wrote:
>>> Hello,
>>> Please review this small fix which deprecate -Xoss, -Xsqnopause,
>>> -Xoptimize and -Xboundthreads options in JDK 9. Also, I need a sponsor
>>> for this fix, who can push it.
>> I can sponsor this for you. But first ...
> Thank you!
>>> Currently HotSpot silently ignore these 4 options. Here are description
>>> of these options:
>>> "-Xoss", "-Xsqnopause", "-Xoptimize" - EVM option leaved for
>>> compatibility. From Java 2 SDK for Solaris Developer's Guide: "Prior to
>>> version 1.3.0, the production releases of the Java 2 SDK for the Solaris
>>> Operating Environment shipped with a virtual-machine implementation
>>> known as the Exact VM (EVM). Beginning with version 1.3.0, the Exact VM
>>> is replaced by the Java HotSpot VM.". So, from Java 1.4 EVM is not used
>>> as VM for JDK on Solaris and these very old flags just silently ignored
>>> by HotSpot.
>>> "-Xboundthreads" - was used to bind user level threads to kernel threads
>>> on Solaris in case when new thread library is not available. But old T1
>>> libthread has been removed from Solaris in release 10. JDK9 requires
>>> Solaris 10u9 or higher. So, this flag become useless.
>>> All these options are deprecated, i.e. following warning is printed when
>>> option is specified: "Java HotSpot(TM) 64-Bit Server VM warning: Option
>>> -Xoss was deprecated in version 9.0 and will likely be removed in a
>>> future release.". In next major release all these options can be
>>> removed.
>>> Webrev: http://cr.openjdk.java.net/~ddmitriev/8078399/webrev.00/
>>> <http://cr.openjdk.java.net/%7Eddmitriev/8078399/webrev.00/>
>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8078399
>>> Tested: JPRT
>> Can you not add these options to the set of obsolete_flags ? (and
>> delete the code that references them of course)
> Unfortunately, I not understand what set of obsolete flags you mean. Do
> you mean os::obsolete_option method or obsolete_jvm_flags table? Since
> obsolete_jvm_flags is developed for "XX:" options I not see how it
> easily can be done. In case of os::obsolete_option methods then I will
> need to add these options to all implementations. Probably, I not
> understand you correctly.

It was the obsolete_jvm_flags table I meant - sorry about the typo. Pity 
it doesn't support -X options. :(

My only suggestion here is to at least use the same warning message as 
would be seen for obsolete -XX flags (something I should have suggested 
when reviewing the CCC request):

warning("ignoring option %s; support was removed in %s", 
stripped_argname, version);


  > java -XX:+UseOldInlining -version
Java HotSpot(TM) Server VM warning: ignoring option UseOldInlining; 
support was removed in 9.0


 > java -Xoss -version
Java HotSpot(TM) Server VM warning: Option -Xoss was deprecated in 
version 9.0 and will likely be removed in a future release.

and if you use an actual JVM_Version then this won't need to be updated 
when the new version string comes in. :)


> Thanks,
> Dmitry
>> Thanks,
>> David
>>> Thanks,
>>> Dmitry

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