8186248 - Allow more flexibility in selecting Heap % of available RAM

[White, Derek]

Hi Bob,

Do you want to add the old flags to the special_jvm_flags list, to get "deprecated" warnings? Or will that come later after CCC-like approval?

 - Derek

> -----Original Message-----
> From: hotspot-runtime-dev [mailto:hotspot-runtime-dev-
> bounces at openjdk.java.net] On Behalf Of Bob Vandette
> Sent: Tuesday, August 22, 2017 2:22 PM
> To: hotspot-runtime-dev at openjdk.java.net runtime <hotspot-runtime-
> dev at openjdk.java.net>; hotspot-gc-dev at openjdk.java.net
> Subject: RFR: 8186248 - Allow more flexibility in selecting Heap % of available
> RAM
> 
> Please review the updated webrev which adds new VM flags to allow for the
> manual selection of Heap size based on a percentage of total available
> memory.
> 
> This version deprecates the existing fractional options and allows the new %
> based flags to override.
> 
> http://cr.openjdk.java.net/~bobv/8186248/webrev.01/
> <http://cr.openjdk.java.net/~bobv/8186248/webrev.01/>
> 
> Bob.
> 
> 
> > On Aug 17, 2017, at 12:36 AM, David Holmes <David.Holmes at oracle.com>
> wrote:
> >
> > On 17/08/2017 1:29 PM, Bob Vandette wrote:
> >> I saw that but wasn't sure it needed the added flexibility since its probably
> ok that initial sizes are 50% or less.
> >
> > I'd go for consistency.
> >
> > Also now you will need to guard against values < 1, I think.
> >
> > There may be an option checking test that will need updating as well.
> >
> > Cheers,
> > David
> >
> >> Bob.
> >>> On Aug 16, 2017, at 5:04 PM, David Holmes <david.holmes at oracle.com>
> wrote:
> >>>
> >>> Hi Bob,
> >>>
> >>>> On 17/08/2017 3:32 AM, Bob Vandette wrote:
> >>>> Please review this simple two line fix which allows more
> >>>> flexibility in selecting the % of system RAM to be used by the Heap.  This
> just changes two int variables to doubles.
> >>>> RFE:
> >>>> https://bugs.openjdk.java.net/browse/JDK-8186248
> >>>> <https://bugs.openjdk.java.net/browse/JDK-8186248>
> >>>> Webrev:
> >>>> http://cr.openjdk.java.net/~bobv/8186248
> >>>> <http://cr.openjdk.java.net/~bobv/8186248>
> >>>
> >>> Wouldn't you also want/need to change the type of InitialRAMFraction?
> >>>
> >>> Note: jdk10/hs is currently closed to changes as we prepare to push up
> to jdk10/jdk10.
> >>>
> >>> Thanks,
> >>> David
> >>>
> >>>> Bob.