[Vm-dev] Re: [squeak-dev] uncompacting classes

Mariano Martinez Peck marianopeck at gmail.com
Thu Dec 1 09:02:23 UTC 2011


>
>>> Eliot, a simple question: In Pharo:
>>> Smalltalk compactClassesArray asSet size -> 15
>>> Smalltalk compactClassesArray asSet size -> 13
>>>
>>> I would like to have one extra free bit in the object header. I can hack
>>> my own VM which uses 4 bits for CompactClasses rather than 5, but do you
>>> think we can do this for the official Cog VM as well? this would allow
>>> "researched" a much nice infrastructure out of the box. How much work can
>>> be such change? is there someone needing 32 compact classes?  if I do a
>>> SpaceTally new printSpaceAnalysis  it looks like if I only need the first
>>> 10 classes....
>>>
>>> I know in the future you want to change all this thing about compact
>>> classes, but if we can have one free bit tomorrow (instead of "in the
>>> future"), then this is very very good.
>>>
>>
>> Seems reasonable.  What do you think Andreas, David, Esteban, Ian?  Shall
>> we make this change?
>>
>
> Belay that.  It doesn't fly.  Bitmap is at index 16, not 15.  So close.
>  Ah well...  Mariano, you could perhaps make it an option.
>
>

Hi Eliot. Just to understand, what is the problem that Bitmap index is 16?
It is not possible to uncompact and compact again or something like this to
assign Bitmap the next "free index" ?   Bitmap is not in
#checkAssumedCompactClasses

Thanks



>
>>
>>>
>>> Thanks in advance,
>>>
>>>
>>>
>>>
>>>>
>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>> Can compact classes be made uncompact when running the
>>>>>>> StackInterpreter VM?
>>>>>>>
>>>>>>
>>>>>> It is exactly the same story.  The same classes are assumed to be
>>>>>> compact in the StackInterpreter VM as the CoInterpreter VM.
>>>>>>
>>>>>>
>>>>>>> Thanks.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> HTH
>>>>>> --
>>>>>> best,
>>>>>> Eliot
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Mariano
>>>>> http://marianopeck.wordpress.com
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> best,
>>>> Eliot
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Mariano
>>> http://marianopeck.wordpress.com
>>>
>>>
>>>
>>
>>
>> --
>> best,
>> Eliot
>>
>>
>
>
> --
> best,
> Eliot
>
>
>


-- 
Mariano
http://marianopeck.wordpress.com
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