[Vm-dev] Re: [Pharo-dev] blog post

[Eliot Miranda]

On Sat, Sep 7, 2013 at 10:38 AM, Florin Mateoc <florin.mateoc at gmail.com>wrote:

>
>
> Hi Eliot,
>
>
> > Eliot Miranda <eliot.miranda at gmail.com <http://lists.squeakfoundation.org/mailman/listinfo/vm-dev>> wrote:
> >
> > Hi Stéph,
> >
> > On Fri, Sep 6, 2013 at 9:35 AM, Stéphane Ducasse
> > <stephane.ducasse at inria.fr <http://lists.squeakfoundation.org/mailman/listinfo/vm-dev>>wrote:
> >
> >* Hi eliot*>>**>*> This is really good that you write this blog. I read and I saw ephemerons*>*> (excellent because we were discussing them again today with esteban and*>*> igor)*>*> I have some questions that may be are stupid.*>*>         - I was wondering if you plan to have a dedicated class space.*>*> Clement told me that in Chrome (but I may be wrong) they have that and in*>*> the class space the classes are not moved. But with the table you are sure*>*> that your index do not change so may be the gain is not important.*>>**>
> > exactly.
>
>
> Wouldn't a fixed, dedicated, class space facilitate though sharing between multiple images?
> This was a nice feature in VW, and I think it may become even more important with the trend towards multi-core.
>
> I also assume that a dedicated space for pinned memory might also simplify the garbage collector and even help performance a bit.
>
> To me it appears that this kind of specialization of memory (splitting it into dedicated spaces) would almost always be a win.
> While it increases the complexity by increasing the number of components to manage, it also simplifies the components, since they need to handle fewer special cases.
> But I have never implemented a vm :)
>
> I am also curious if you are including immediate floats in your 64-bit object format.
> I am sure you know about it, but I saw this nice article about tagging in the current JavaScript implementations:http://wingolog.org/archives/2011/05/18/value-representation-in-javascript-implementations
>
>
Yes, NaN-boxing is a good name for an old idea.  Very cute.  But I'm not
going there. :-)  Too much legacy, plus Smalltalk isn't JavaScript
(JavaScript doesn't have integers except inside certain VMs).


> You only mentioned in your blog tagging for the 32-bit world (I think).
> Can you please add some comments about 64-bit tagging?
>
> Regards,
> Florin--
>
> best,
Eliot
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