crb002 / gmail.com wrote:
> I have an application where I need to sort objects based on their
> memory footprint. What is the easiest way to get this information
> from  Ruby1.6 ? I have no problem with having to call some C functions
> to get this info.
> 
> The hack Marshal.dump(foo).size() would work, but since this might be
> called often I need an elegant solution.
> 
> 

Hmmm...tricky. Seems like you'd want a #footprint method in every class 
that accumlated the memory footprint of the object. That method would be 
written in C so it could account for the sizes of the C structure 
(RString, RArray, etc.) that represents the object. You'll have to make 
some rules about collections. Does the footprint of an array include the 
footprints of the object in the array, or just the container? Same for 
Hash, etc. Then there's going to be some objects for which you just 
can't get an accurate count. I suspect it would be hard to find out how 
much memory is allocated to buffers for an open file, for example (if 
that matters). And I  know for a fact that you can't find out how much 
memory is allocated to one of RMagick's Magick::Image objects. Even the 
Marshal hack wouldn't work there since the on-disk size doesn't have to 
match the in-memory size. Of course your application may not use such 
objects, but they exist.

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