volker.simonis at gmail.com
Tue Nov 27 02:21:33 PST 2007
On 11/26/07, Tom Rodriguez <Thomas.Rodriguez at sun.com> wrote:
> Also the ProfileInterpreter option does nothing with the C++ interpreter
> so any benchmarks which benefit from type profiling will run more slowly
> with the C++ interpreter.
Thats right. But we use the C++-Interpreter for our IA64, PPC and s390
ports and we have extended the C++-Interpreter to use profiling.
Unfortunately this is still in Java 5. So the plan is to downport the
C++-Interpreter from Java 7 to Java 6 and integrate our changes from
Java 5 into Java 6. Than we can do a new shootout and compare the
template interpreter with a profiling C++-Interpreter to see what we
really loose by using the C++-Interpreter.
> steve goldman wrote:
> > Volker Simonis wrote:
> >> If you are interested in a performance comparison between the C++ and
> >> the Template Interpreter you may want to read the following blog:
> >> http://weblogs.java.net/blog/simonis/archive/2007/11/template_vs_cin_1.html
> >> "Template- vs. C++-Interpreter shootout: This blog discusses the main
> >> differences between the C++ and the Template Interpreter which are
> >> both available within the Hotspot sources of the OpenJDK project. Some
> >> performance tests with the DaCapo benchmark suite which compare the
> >> two interpreters in mixed and interpreted mode on Linux/x86 and
> >> Solaris/SPARC conclude the presentation."
> > Very cool. So the results are much different (worse) for Xmixed than I
> > got in the long distant past. Server has certainly changed a lot in the
> > interim. So what compiler did you use on Solaris? Considering how
> > similar the numbers are between x86/sparc for -Xint it would seem that
> > you might have used gcc. I used to see worse behavior on sparc because
> > with gcc the interpreter could do the computed goto trick for the
> > dispatch loop and that is worth a lot.
> > Second if you have the time it would interesting to see the comparison
> > using client.
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