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

Srinivas Ramakrishna ysr1729 at gmail.com
Thu Dec 20 01:19:08 PST 2012


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>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/
>
> 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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