Getting rid of Compact classes (Was: Re: [squeak-dev] The Primitive: I am not a number- I am a named prim! - SqueakPeople article)

Igor Stasenko siguctua at gmail.com
Tue Jul 1 02:21:35 UTC 2008


2008/7/1 John M McIntosh <johnmci at smalltalkconsulting.com>:
>> The image size is 36368500 bytes. So, in percentage its roughly 6%
>> space increase.
>>
>> I can't measure how faster (or slower) image would be if we remove
>> compact classes, because it requires a conversion :)
>>
>> -- Best regards,
>> Igor Stasenko AKA sig.
>
>
>
> Eliot was discussing with me removing compact classes for Cog a couple of
> weeks back. He ran a quick calculation and I *thought* it was
> more like 12%.  Although 12% seem excessive since every byte counts in your
> iPhone, we debated with no
> conclusion if we should trade the memory for better performance.
>

On iPhone you will definitely use smaller image, where percentage will
be different.
So, its really depends on image. The more percentage of instances
using compact classes, the more difference is.
>From this point, for space economy, i would expect to see all slots in
compact classes array to be filled with most used classed.
But why then its not used at full throttle in squeak?

Seriously, if we could have a code which can translate all compact
instances back and forth, then we could measure it more precisely.

> Personally  I'd think the user would want better performance over the
> developer's desire to that extra 4 mb of memory somewhere..
> .
> --
> ===========================================================================
> John M. McIntosh <johnmci at smalltalkconsulting.com>
> Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
> ===========================================================================
>
>



-- 
Best regards,
Igor Stasenko AKA sig.



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