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From "Weldon Washburn" <weldon...@gmail.com>
Subject Re: [DRLVM][JET] write barrier for Java (mmtk)
Date Wed, 11 Oct 2006 06:18:00 GMT
Ooops.  I really tangled things up.  You are right about how we are supposed
to find the Java write barrier method.  It is located in Plan.writeBarrier().
Each GC algorithm has a Plan class that overrides the writeBarrier()
method.  I erroneously thought we could call
VM.barriers.performWriteInBarrier() directly.  This sort of, kind of breaks
MMTk architecture.  By design, each GC algorithm in MMTk is supposed to call
Plan.writeBarrier() which, in turn, will call
VM.barriers.performWriteInBarrier.

Sorry for the confusion.




On 10/10/06, Mikhail Fursov <mike.fursov@gmail.com> wrote:
>
> Yes, we can run the usual inliner after helpers are inlined.
> The only problem I want to notice is that once we have different helpers
> for
> different GCs it's a bad idea to use virtual method calls in performance
> sensitive helpers. You are allowed to do it, but the better solution is to
> teach the helper to use a final implementation of the Barrier and replace
> the helper once the implementation of the Barrier class is changed.
>
> On 10/11/06, Rana Dasgupta <rdasgupt@gmail.com> wrote:
> >
> > Makes sense, using a standard barrier invocation fastpath. But I assume
> > that
> > the MMTk WB helper that it will call needs to be inlined too.
> >
> > Thanks
> >
> >
> > On 10/10/06, Mikhail Fursov <mike.fursov@gmail.com> wrote:
> > >
> > > Weldon,
> > > > I thought about slightly different approach.
> > > > Why not to write fast-path VM helper like was proposed in the thread
> > > > "[drlvm]Extending..."
> > > > This helper (a static method) can be inlined by JIT without any
> > > > devirtualization and call any method needed from MMTk or native
> > > > implementation. So JIT won't know if it works with MMTk or with a
> > native
> > > > GC:
> > > > all you need is just to replace the Java version of the helper.
> > > > ?
> > > >
> > >
> > >
> >
> >
>
>
> --
> Mikhail Fursov
>
>


-- 
Weldon Washburn
Intel Middleware Products Division

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