High Memory Consumption

[Tasiro]

Const $fill_size = 2 ^ 24 ; change should be visible in task manager

Func test ()
	Local $arr [$fill_size]
	MsgBox (0, "", "Ready?")
	$arr [0] = $arr
	MsgBox (0, "1/2 times", "Ready?")
	$arr [1] = $arr
	MsgBox (0, "2/3 times", "Ready?")
	$arr [2] = $arr
	MsgBox (0, "3/4 times", "Ready?")
	$arr [3] = $arr
	MsgBox (0, "4/5 times", "Ready?")
	$arr [4] = $arr
	MsgBox (0, "5/6 times", "Ready?")
	Return $arr
EndFunc

Func test2 ()
	Local $arr [$fill_size]
	MsgBox (0, "", "Ready?")
EndFunc

MsgBox (0, "", "Start" & @CRLF & "- open the task manager")
test2 ()
MsgBox (0, "", "Free")
test ()
MsgBox (0, "", "End")

Memory usage differs between v3.3.9.21 and v3.3.8.1. (v3.3.9.21 with GC?)

Why is so much memory consumed? When exactly was something copied? When assigning a value? When returning a value? When passing a value as an argument? When not? Please update the documentation.

[BrewManNH]

I don't see much difference in memory usage between 3.3.9.21 and 3.3.8.1, there's a slight difference on my computer, but not a whole lot.

If you're asking why it uses so much memory in the second test, it's because you keep putting the array into itself, every time you do that you're going to use a LOT of memory. I'm not sure what exactly the issue you're complaining about is, maybe you should write it out more clearly explaining EXACTLY what you think is wrong.

[Tasiro]

There is a difference of 66 MB after the execution of line 6.

Why does it need memory to copy a pointer? No memory is consumed in the statement $arr [0] = $arr (v3.3.8.1).

[BrewManNH]

Who says it's copying a pointer? It's copying the contents of the array $arr into element 0 of $arr so in effect you've just doubled the memory needed to hold $arr. Doing it again into element 1 means you now need to triple the memory needed to hold $arr and so on and so on.

[Tasiro]

Const $size = 2 ^ 24

Func test ()
    Local $arr [$size]
    MsgBox (0, "", "1")
    $arr [0] = $arr
    MsgBox (0, "", "2")
    $arr [1] = $arr
    MsgBox (0, "", "3")
    $arr [2] = 1
    MsgBox (0, "", "4")
    $arr [3] = 2
    MsgBox (0, "", "5")
    $arr [4] = $arr
    MsgBox (0, "", "6")
    $arr [5] = 3
    MsgBox (0, "", "7")
EndFunc

test ()

AutoIt 3.3.8.1

message box	memory	change	operation
1	69.912 KB	+69.912 KB	Dim $arr [$size]
2	69.928 KB	+16 KB	$arr [0] = $arr
3	135.600 KB	+65.672 KB	$arr [1] = $arr
4	201.268 KB	+65.668 KB	$arr [2] = 1
5	201.268 KB	+0 KB	$arr [3] = 2
6	201.268 KB	+0 KB	$arr [4] = $arr
7	266.936 KB	+65.668 KB	$arr [5] = 3

Well, I think this behavior is strange. Why is the memory allocation delayed?

[jchd18]

Trac is for reporting confirmed bugs, not asking for implementation details you "think" are strange.
FYI, AutoIt uses COW.

[Jos]

Please discuss in our forums and only report confirmed bug here.

Cheers,
Jos