[EXTERNAL] Re: RFR(M): 8248190: PPC: Enable Power10 system and use new byte-reverse instructions

[joserz at linux.ibm.com]

Hallo Martin!

Just to understand. Do I need to do something else? Ask more reviewers?

Thank you :)

Jose

On Fri, Aug 21, 2020 at 03:25:46PM +0000, Doerr, Martin wrote:
> Hi Thomas,
> 
> I understand your point. My concern is that it may become a more political discussion how to handle CSR for PPC64 flags and I don't want to delay Jose's change for that. There are already other changes in the pipe which build on top of it.
> 
> It will probably be us to handle and approve CSR requests for platforms which are maintained by SAP. We haven't done this so far. We are still handling such flags in a less formal way.
> I don't know how other non-Oracle platforms are handled.
> 
> Best regards,
> Martin
> 
> 
> > -----Original Message-----
> > From: Thomas Schatzl <thomas.schatzl at oracle.com>
> > Sent: Freitag, 21. August 2020 17:12
> > To: Doerr, Martin <martin.doerr at sap.com>; joserz at linux.ibm.com
> > Cc: hotspot-compiler-dev at openjdk.java.net
> > Subject: Re: [EXTERNAL] Re: RFR(M): 8248190: PPC: Enable Power10 system
> > and use new byte-reverse instructions
> > 
> > Hi,
> > 
> > On 21.08.20 17:06, Doerr, Martin wrote:
> > > Hi Thomas,
> > >
> > > I agree with you in general. However, all PPC64 specific platform flags are
> > "product" at the moment.
> > > Most of them should probably be "diagnostic". We should fix that at some
> > point of time.
> > > But for now, I'm ok with Jose's webrev since it's consistent with the other
> > PPC64 flags.
> > >
> > 
> >    I was merely pointing out what the rule is, that has not been a veto
> > for the patch (which I haven't reviewed btw). If you want to go ahead
> > with that for consistency's sake, with a plan to fix this I can see your
> > point of keeping it.
> > 
> > Thanks,
> >    Thomas
> > 
> > > Best regards,
> > > Martin
> > >
> > >
> > >> -----Original Message-----
> > >> From: hotspot-compiler-dev <hotspot-compiler-dev-
> > >> retn at openjdk.java.net> On Behalf Of Thomas Schatzl
> > >> Sent: Freitag, 21. August 2020 15:45
> > >> To: joserz at linux.ibm.com
> > >> Cc: hotspot-compiler-dev at openjdk.java.net
> > >> Subject: Re: [EXTERNAL] Re: RFR(M): 8248190: PPC: Enable Power10
> > system
> > >> and use new byte-reverse instructions
> > >>
> > >> Hi,
> > >>
> > >> On 21.08.20 15:37, joserz at linux.ibm.com wrote:
> > >>> Hello!
> > >>>
> > >>> On Fri, Aug 21, 2020 at 10:04:38AM +0200, Thomas Schatzl wrote:
> > >>>> Hi,
> > >>>>
> > >>>> On 21.08.20 04:33, Michihiro Horie wrote:
> > >>>>>
> > >>>>> Hi Jose,
> > >>>>>
> > >>>>> One thing I noticed is a misaligned backslash in globals_ppc.hpp.
> > >>>>> Otherwise, the change looks good!
> > >>>>>
> > >>>>>       /* special instructions */
> > >>>>> \
> > >>>>> +  product(bool, UseByteReverseInstructions, false,
> > >>>>> \
> > >>>>
> > >>>> Fwiw, for adding product options, you must go through the CSR
> > process.
> > >> Maybe
> > >>>> there is an exception for platform specific ones?
> > >>>
> > >>> I didn't find any exception for platform specific options. But,
> > >> "experimental" options
> > >>> don't need such CSR process and, to be honest, experimental seems
> > more
> > >> appropriate here.
> > >>> What do you think?
> > >>>
> > >>> Thank you for your review! :)
> > >>
> > >> Just a fly-by. It's up to you :) - just that product options need to be
> > >> announced to the world.
> > >>
> > >> I kind of agree that experimental seems more appropriate. You can
> > always
> > >> "upgrade" it later.
> > >>
> > >> Thomas
>