[Openmcl-devel] memory

Joakim Sandgren joakim at joakimsandgren.com
Mon Apr 12 14:16:43 UTC 2010


In my case I have an object that contains all structures and data for  
a whole musical composition.
parts, measures, notes, pitchvalues mapping tables...
It would be good to be able to see the "footprint" of different types  
of solution.
as you are always confronted with either big size and high speed, or  
smaller size and more calculations and then slower speed.

sincerely
joakim


Le 12 avr. 10 à 06:45, Gary Byers a écrit :

> When people ask questions like this, they usually means something
> like "what's the total size of this object, plus the size of all  
> things that
> it transitively and uniquely references ?"
>
> Another way of asking that is to ask "if the object in question  
> became garbage, how
> much memory would be freed by the GC ?"
>
> (let* ((obj (make-instance ...)))
> (gc)
> (let* ((with-obj (%precise-size-of-allocated-memory-at-the-moment)))
>   (setq obj nil)
>   (gc)
>   (let* ((without-obj (%precise-size-of-allocated-memory-at-the- 
> moment)))
>     (- with-obj without-obj))))
>
> There's no such function as the one that I'm calling %PRECISE-SIZE- 
> OF-ALLOCATED-MEMORY-AT-THE-MOMENT; it's very hard to measure this in  
> CCL (because of threads and because of other issues.)  We're also  
> assuming that OBJ is the only thing that becomes garbage between the  
> two GCs, and we're assuming that that object isn't sitting in some  
> machine register even after we set the variable OBJ to NIL.  Neither  
> of those assumptions is valid.
>
> I don't want to say that there's no reliable way to answer this  
> question in general, but it's much, much harder to answer than it  
> might appear to be at first glance.
>
> There are some heap-analysis utilities described at <http://trac.clozure.com/ccl/wiki/MemoryUtils 
> > (some of them are currently x8664-Linux-specific); none of them  
> try to answer this question, but they do try to answer some similar  
> questions.
>
>
>
> --On April 11, 2010 4:50:23 PM +0200 Joakim Sandgren <joakim at joakimsandgren.com 
> > wrote:
>
>> Hi,
>> Are there a way to see how big in Kb  or bytes a clos object is ?
>>
>>
>> sincerely
>> joakim
>>
>>
>>
>>
>>
>>
>>
>>
>> Joakim Sandgren
>> joakim sandgren musik
>> 42, rue de Maubeuge
>> 75009 Paris
>> France
>> +33 (0)1 45 26 43 90
>> info at joakimsandgren.com
>> http://www.joakimsandgren.com
>
>
>
>




Joakim Sandgren
joakim sandgren musik
42, rue de Maubeuge
75009 Paris
France
+33 (0)1 45 26 43 90
info at joakimsandgren.com
http://www.joakimsandgren.com

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