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From "Pavel Afremov" <pavel.n.afre...@gmail.com>
Subject Re: [drlvm][gcv5] finalizer design
Date Mon, 18 Dec 2006 16:44:55 GMT
On 12/18/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
>
>
> But don't you then make it harder to port?
>
>

 It's makes porting a bit harder, but not very, I think. The main point now
to avoid regression. I think GC v5 should support Work Balance Subsystem, or
something like it before it becomes main GC for DRLVM. Also GC v5 should
works with "java" implementation of finalization system correctly, in any
case VM and GC implementations should be independent on each other.



BR

Pavel Afremov.


On 12/18/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
>
>
>
> Xiao-Feng Li wrote:
>
> [SNIP]
>
> > 3 . We think a native thread Finalizer solution is better than a Java
> > thread solution. Since the Java thread actually runs in a native
> > thread, we don't need the extra wrapper.
>
> Really?
>
> [SNIP]
>
> >
> > Explanations to  3 .
> >  - In Java finalizer thread implementation, there exists potential
> > circular dependence between the Java thread startup and JVM
> > bootstrapping. The bootstrapping issues or bugs with Java code in VM
> > were discussed more than once.
> >  - In Java finalizer thread implementation, there are rounds of
> > redundant steps to do finalization with Java thread. In existing Java
> > thread implementation, to execute the finalizers, VM native calls Java
> > method startFinalization to wakeup finalizer threads. The finalizer
> > Java threads call a native method doFinalization to excute the
> > finalizers. This native method accesses native queue and calls Java
> > finalizer method again. With a native thread finalizer, it simply
> > calls the Java finalizer directly without all other boundary
> > crossings.
> >  - A java finalizer thread finally maps to a native thread managed by
> > VM. This extra mapping is unnecessary.
> >  - Finalizer threads are VM internal entities. VM may want to
> > schedule it as it wants for load balance or helper threading. This is
> > much easier with the direct native threads.
> >  - With native thread finalizer, we can share the same thread pool
> > with other VM components such as GC, etc. This helps to manage the
> > system overall performance and scalability, and it's easier.
> >  - DRLVM is in written in C++, its components interact through native
> > interfaces. It is natural for VM core components written in native
> > code.
>
> But don't you then make it harder to port?
>
>
> geir
>

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