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List:       openjdk-hotspot-runtime-dev
Subject:    RE: RFR(M): 8168083: PPC64: Cleanup template interpreter after 8154580 and 8154867
From:       "Doerr, Martin" <martin.doerr () sap ! com>
Date:       2016-10-27 10:10:13
Message-ID: 39282c5a307648cb931e0c2781cc5810 () DEWDFE13DE10 ! global ! corp ! sap
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Hi Coleen,

thanks for your email and for opening the bug.

Reloading of ConstMethod is not restricted to load_mirror(). E.g. SPARC's \
generate_fixed_frame loads it 4 times. Therefore, I have added a comment to the bug.
I guess the load_mirror change alone is not so relevant, but I appreciate any cleanup \
there as well.

Thanks and best regards,
Martin


-----Original Message-----
From: Coleen Phillimore [mailto:coleen.phillimore@oracle.com] 
Sent: Mittwoch, 26. Oktober 2016 21:32
To: Doerr, Martin <martin.doerr@sap.com>; hotspot-runtime-dev@openjdk.java.net
Subject: Re: RFR(M): 8168083: PPC64: Cleanup template interpreter after 8154580 and \
8154867



On 10/20/16 4:58 AM, Doerr, Martin wrote:
> Hi Coleen,
> 
> thank you very much for reviewing my PPC change.
> 
> We had originally spent a lot of effort to get the template interpreter fast. I \
> think startup performance is still important. A large amount of less optimized \
> changes will make it slower over time. That's why we have reduced reloading \
> constMethod in the PPC implementation. I think this would be good for other \
> platforms as well. Maybe we should improve them in 10.

I don't know. I though load_mirror() made for a nice API.  Does the extra indirect \
matter?  I filed RFE https://bugs.openjdk.java.net/browse/JDK-8168795 so we can \
investigate further in 10.

This is approved and I think reviewed so you can check it in anytime.  I 
put a due date of Friday on your bug.   Feel free to change it if that's 
not good.

Thanks,
Coleen

> 
> Best regards,
> Martin
> 
> 
> -----Original Message-----
> From: hotspot-runtime-dev 
> [mailto:hotspot-runtime-dev-bounces@openjdk.java.net] On Behalf Of 
> Coleen Phillimore
> Sent: Dienstag, 18. Oktober 2016 23:56
> To: hotspot-runtime-dev@openjdk.java.net
> Subject: Re: RFR(M): 8168083: PPC64: Cleanup template interpreter 
> after 8154580 and 8154867
> 
> 
> This seems good.   I think it's a shame to change load_mirror() to
> load_mirror_from_const_method() though because there's load_mirror() 
> with the same parameters on all the other platforms and it makes
> platform development a little easier.   But that's up to you to because
> you can generate shorter sequences.
> 
> Coleen
> 
> 
> On 10/17/16 12:38 PM, Doerr, Martin wrote:
> > Hi,
> > 
> > I'd like to clean up the template interpreter on PPC64 a little bit after changes \
> > which were pushed into jdk9: 
> > 8154580 introduced copying the java mirror into the interpreter frame. Some code \
> > can be implemented shorter. Before this change, the size of the ijava state was \
> > designed to be a multiple of 16. We should remove the comment as this is no \
> > longer true. I have checked that this is not really required \
> > (generate_fixed_frame inserts frame padding if needed). 
> > 8154867 is the PPC64 port of "better byte behavior". The shorter TOS states are \
> > not treated appropriately (which is not critical because the template interpreter \
> > also uses itos for shorter types). This part of the change was requested by \
> > Coleen, but it didn't make it into the original webrev. 
> > Webrev is here:
> > http://cr.openjdk.java.net/~mdoerr/8168083_PPC64_interp_cleanup/webre
> > v.00/
> > 
> > Please review.
> > 
> > Thanks and best regards,
> > Martin
> > 


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