Ok, the problem was that I was doing:

usedMemory := usedMemory + self internalByteSize: oop.

that didn't work and always answered me the same number.

Now, I had to do this:

usedMemory := usedMemory + (self internalByteSize: oop).

I don't understand why.

Thanks

Mariano

On Thu, Apr 29, 2010 at 3:22 PM, Mariano Martinez Peck <marianopeck@gmail.com> wrote:



It's close but not entirely correct. The computation needs to include the extra header word for "large" instances (> 255 bytes). Squeak has three possible header sizes:

� � � �1 header word �- used by compact classes
� � � �2 header words - used by regular classes
� � � �3 header words - used by "large" instances

BTW, SpaceTally>>spaceForInstancesOf:withInstanceCount: has the correct computation (except for 64 bit :-)


Ok, perfect. Thanks :)

�

Is there a way to know this
but from the VM side also ? how ?
I really need it from the VM side :( �but I have no idea how to do it.

It's easy to do in the VM, just use this:

primitiveByteSize
� � � �"Answers the number of bytes the receiver occupies"

� � � �| nbytes|
� � � �self export: true.
� � � �oop := self popStack.
� � � �nbytes := (self sizeBitsOf: oop) + (self extraHeaderBytes: oop).
� � � �self pushInteger: nbytes.



I tried this and seems to work ok. I don't really need a primitive but an internal method that is called by a primitive. So, I did something like this:

internalByteSize: anOop

������ "Answers the number of bytes the receiver occupies"
������ | nbytes|
������ self inline: true.
������ nbytes := (self sizeBitsOf: anOop) + (self extraHeaderBytes: anOop).
������ ^ nbytes.



and then I call it like this for example:

oop := self firstAccessibleObject.
��� [oop = nil] whileFalse: [
��� ��� (self isIntegerObject:� oop)
��� ��� ��� ifFalse: [
��� ��� ��� ��� size :=� self internalByteSize: oop.
���������� ......]
� oop := self accessibleObjectAfter: oop.
��� ].

�
but internalByteSize ALWAYS return me the same value...do you know what can be wrong ?

Thanks in advance

Mariano