jdk 9 performance optimizations

[Jeroen Borgers]

Hi Christian,

Thanks for the clarification, I over-simplified. Can you please shed some
light on my questions? How can jigsaw help with AOT, inlining lambda's?
I did my jug talk already yesterday, yet, I am curious.
Thanks!

Jeroen

2015-11-05 21:27 GMT+01:00 Christian Thalinger <
christian.thalinger at oracle.com>:

>
> > On Nov 3, 2015, at 12:26 PM, Jeroen Borgers <jborgers at jpinpoint.com>
> wrote:
> >
> > I posted in jigsaw-dev list before:
> >
> > I found this interesting presentation "Java goes AOT" from JVM Language
> > Summit: https://www.youtube.com/watch?v=Xybzyv8qbOc
> >
> > As presented by Christiaan Thalinger from HS compiler team, AOT is used
> > with Graal to reduce startup time and quicker peakperformance (tiered).
> > Currently they don't do any inlining in AOT yet
>
> That’s not accurate; we do inlining but very limited.
>
> > because compilation time
> > blows up by inlining everything since no profiling information is
> available
> > yet. I guess modules and knowing dependencies can help here to reduce
> this.
> > Besides test running to generate profiling data.
> >
> > Regards, Jeroen
> > Bijlagen
> > Voorbeeld van YouTube-video JVMLS 2015 - Java Goes AOT weergeven
> > JVMLS 2015 - Java Goes AOT
> > Vitaly Davidovich
> > 13:09 (10 uur geleden)
> > aan Jeroen, jigsaw-dev
> >
> > Yes, I had seen Chris' presentation as well.  Certainly modularization
> will
> > help AOT in many ways.  But, I'm particularly interested on the JIT side.
> > What was meant by aggressive lambda inlining, for example? Can anyone
> point
> > at some additional info?
> >
> > Thanks
> >
> > sent from my phone
> > Paul Sandoz <paul.sandoz at oracle.com>
> > 13:32 (9 uur geleden)
> > aan jigsaw-dev
> > Hi Vitaly,
> >
> > Probably worth sending an email to the hotspot-dev at openjdk.java.net
> <mailto:
> > hotspot-dev at openjdk.java.net>
> >
> >> On 3 Nov 2015, at 13:09, Vitaly Davidovich <vitalyd at gmail.com> wrote:
> >>
> >> Yes, I had seen Chris' presentation as well.  Certainly modularization
> > will
> >> help AOT in many ways.  But, I'm particularly interested on the JIT
> side.
> >> What was meant by aggressive lambda inlining, for example? Can anyone
> > point
> >> at some additional info?
> >>
> >
> > I presume it in part might relate to cracking open the lambda “box”
> > implementing the targeted functional interface to obtain the underlying
> > method containing the lambda body, generated by javac, that the box
> defers
> > to, then subsituting the indy call to an invocation of that underlying
> > method. Cue lots of hand waving…
> >
> > Maybe more clues in Oleg Pliss’s Closures on Embedded JVM presentation at
> > JVMLS 2014:
> >
> >  http://www.oracle.com/technetwork/java/jvmls2014pliss-2265210.pdf <
> > http://www.oracle.com/technetwork/java/jvmls2014pliss-2265210.pdf>
> > --------
> >
> > Thanks,
> >
> > Jeroen
> >
> > 2015-11-03 23:21 GMT+01:00 Jeroen Borgers <jborgers at jpinpoint.com>:
> >
> >> Hi,
> >>
> >> One of the goals of Jigsaw that intrigue me, I read here:
> http://openjdk.
> >> java
> >>
> .net/projects/jigsaw/goals-reqs/03#enable-ahead-of-time-whole-program-optimization-techniques
> >> is:
> >> *Enable ahead-of-time, whole-program optimization techniques*  -
> >> [..]
> >> The optimization techniques envisioned here include, but are not limited
> >> to: Fast lookup of both JDK and application classes; early bytecode
> >> verification; aggressive inlining of, *e.g.*, lambda expressions, and
> >> other standard compiler optimizations; construction of JVM-specific
> memory
> >> images that can be loaded more efficiently than class files;
> ahead-of-time
> >> compilation of method bodies to native code; and the removal of unused
> >> fields, methods, and classes. These kinds of techniques tend to work
> best
> >> when JDK and application code is analyzed together, prior to run time.
> >> [..]
> >>
> >>   -
> >>
> >>   *Optimize existing code as-is* — It must be possible to apply the
> >>   optimizer tool to existing code already packaged in traditional jar
> files,
> >>   without changing those files.
> >>   -
> >>
> >>   *Actual optimizations* — As a proof of concept, provide at least two
> >>   optimizations that deliver nontrivial performance benefits.
> >>
> >> I am curious about the following:
> >> * What is the current state of this? Which techniques/optimizations are
> >> already implemented and available from the current ea JDK9 or will be?
> >> * Are there any new insights/developments in this area?
> >> * I noticed in my JMH microbenchmark with parallel stream and lambda's
> >> that it runs slightly faster on 9_b85 compared to 8_u66. Could this be
> >> caused by more aggressive inlining of lambda's?
> >> * It seems to me that some compilation and optimization work is moved
> from
> >> runtime to link time /AOT time, yet, we don't have profiling information
> >> there, so this will be limited, right? Are there obvious cases which
> work
> >> well?
> >> * I don't really see why aggressive inlining and std optimizations can
> now
> >> be more effective. Because there will be less de-optimization events
> needed
> >> because of better predictability? Can in-lining now take place in two
> ways,
> >> between platform modules and application? Through interfaces?
> >>
> >> Thanks!
> >> Jeroen
> >>
> >>
> >>
>
>