RFR(XS): 8001424: G1: Rename certain G1-specific flags

John Cuthbertson john.cuthbertson at oracle.com
Thu Dec 20 10:04:23 PST 2012


Hi Ramki, Bengt,

Thanks for the reviews. I kept the old names because the perf team would 
like these backported to hs24 (7u12) and the old names have been 
published in several presentation decks - including one from Monica and 
Charlie at JavaOne. Does it still make sense to just accept the new 
names? The change would be much smaller if so.

Thanks,

JohnC

On 12/20/2012 1:19 AM, Srinivas Ramakrishna wrote:
> New names look good. I agree with Bengt that for renames of exptal 
> flags in a major release bothering supporting old names is not 
> worthwhile; best to
> make a clean break with the old names.
>
> reviewed
> -- ramki
>
> On Wed, Dec 19, 2012 at 10:30 PM, Bengt Rutisson 
> <bengt.rutisson at oracle.com <mailto:bengt.rutisson at oracle.com>> wrote:
>
>
>     Hi again John,
>
>     I realized that I was a bit too fast with my comment about using
>     ObsoleteFlag. Your code is aliasing the old names for the new ones
>     which is something the obsolete flag management does not do.
>
>     But on the other hand, do we really want to do this? These are all
>     experimental flags and we are pushing this change to a major
>     release, JDK8. Personally I don't think it is worth supporting the
>     old names.
>
>     Bengt
>
>
>     On 12/20/12 5:45 AM, Bengt Rutisson wrote:
>>
>>     Hi John,
>>
>>     This looks good. But I think that instead of your change in
>>     arguments.cpp you could make use of the obsolete_jvm_flags list
>>     that exist in the same file. I think that is intended for exactly
>>     this purpose. Accepting a removed flag name for a little while.
>>     The nice thing about it it that you specify how long you will
>>     accept the old name.
>>
>>     static ObsoleteFlag obsolete_jvm_flags[] = {
>>       { "UseTrainGC", JDK_Version::jdk(5), JDK_Version::jdk(7) },
>>
>>     If you use this you also have to remove the old flag names from
>>     globals.hpp.
>>
>>     Bengt
>>
>>
>>     On 12/20/12 1:56 AM, John Cuthbertson wrote:
>>>     Hi Everyone,
>>>
>>>     Some flag name changes suggested by the JVM performance team
>>>     based upon feedback they have received. The webrev can found at:
>>>     http://cr.openjdk.java.net/~johnc/8001424/webrev.0/
>>>     <http://cr.openjdk.java.net/%7Ejohnc/8001424/webrev.0/>
>>>
>>>     Basically the changes are those listed in the webrev:
>>>
>>>     G1DefaultMinNewGenPercent is being replaced by G1NewSizePercent
>>>     G1DefaultMaxNewGenPercent is being replaced by G1MaxNewSizePercent
>>>     G1OldCSetRegionLiveThresholdPercent is being replaced by
>>>     G1MixedGCLiveThresholdPercent
>>>
>>>     Thanks,
>>>
>>>     JohnC
>>
>
>

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