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From "Pavel Ozhdikhin" <pavel.ozhdik...@gmail.com>
Subject Re: [drlvm][em] Value-profiling implementation is avaible.
Date Tue, 31 Oct 2006 06:11:01 GMT
Hello Yuri,

I'm currently condidering different ways of devirtualization improvement in
the JIT compiler. There are many of them and value profiling is one of the
most promising. I would be happy if we could work together on making value
profiling useful in Jitrino.OPT. Currently devirtualizer in JIT can use edge
profile and method hotness profile (in addition to class hierarchy
analysis and preexistence) to guess about receiver type but value
profile must be more precise.

I'd like to look into your patch and play a little with it - could you
please put your code into JIRA and announce its number here?

Thank you,
Pavel Ozhdikhin
Intel Java and XML division


On 10/31/06, Yuri Kashnikoff <yuri.kashnikoff@gmail.com> wrote:
>
> 2006/10/30, Mikhail Fursov <mike.fursov@gmail.com>:
> > Hi Yuri.
> > Value profile is a profile that is really needed for set of JIT
> > optimizations.
> > What do you want to improve in JIT exactly?
> First of all I want to imporove the devirtualization, using value
> profiling feedback. And now I found that some other optimization could
> use value profling, if it is interesting I can put some ideas here for
> considering.
>
> For Geir and other non-Jit-nerds (I'am not JIT-nerd alredy but I'am
> trying to become one of them), I'll try to explain what the value
> profiling is and how it could be used for increasing JIT performance.
>
> Devirtualization of virtual calls.
> We have some virtual calls. And we know that in some program
> realisation of some method A used more often (for examle 1000 times)
> and antoher realisation of this method B used only 10-20 times. So
> this information could be usefull for recompiling the Hot Method A.
> And Value Profiler brings this information to JIT.
>

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