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From Etienne Gagnon <egag...@sablevm.org>
Subject Re: [drlvm][sablevm] Desing of Class Unloading Support
Date Tue, 31 Oct 2006 19:41:24 GMT
Actually, I think that Java vtables would be more expensive than my
proposed approach (when you take my proposed improvements in my reply to
Pavel Pervov), as you add overhead to all GC cycles!  [Unless you don't
"trace" from every visited object to its vtable?]

I really don't like much the idea of an "object" vtable.  It requires
things such as "pinning", etc.  Looks more expensive than my solution.

Etienne

Rana Dasgupta wrote:
> Etienne,
>  This is a good design, thanks. Conceptually, reference counting in the VM
> is somewhat similar to Aleksey's proposal 1, if I understand correctly.
> This
> design also requires quite a few hand-offs between the VM and GC. In DRLVM,
> the problem is that we have quite a few GC's, not all within our control.
>  However, it seems to me that we can either desire to make unloading
> automatic, in which case, we will need things like java vtables etc and
> leave most things to the GC. Or we can do refcounting or tracing in the VM,
> and work lock step with the GC(s). I am not sure which is the better way.

-- 
Etienne M. Gagnon, Ph.D.            http://www.info2.uqam.ca/~egagnon/
SableVM:                                       http://www.sablevm.org/
SableCC:                                       http://www.sablecc.org/

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