Memory Pool – Manual memory management

[ivan.velhoParticipant]

Is there a way  to manually manage memory, like Pool  in Monkey 1 ?

Thanks

[impixiParticipant]

IIRC, there is no Monkey1-like Pool class in MX2’s collections library.

I did some pooling experiments several MX2 releases back. I could not find a solution that performed quicker than run-time Newing of objects, regardless of the quantity (on PC hardware). Memory fragmentation issues, however, are theoretically solved by object pooling.

Here’s a simple generic object pooling class:

Note that any objects added to it require a default New() constructor.

Monkey

[crayon-5cba9b9e6230e135407959 inline="true" ] #import "<std>" Using std.collections '---- Class Pool<T> Private Field _autoResize:Bool Field _autoResizeMultiplier:Float Field _capacity:UInt Field _objs:Stack<T> Method Fill:Void() For Local n:= _objs.Length Until _capacity 'A default constructor (New() without parameters) is required 'otherwise the compiler will raise the following error: 'Can't find overload for 'new(...)' with argument types () _objs.Push(New T()) Next End Public Method New(capacity:UInt = 10, autoResize:Bool = True, autoResizeMultiplier:Float = 2.0) _objs = New Stack<T> Capacity = capacity AutoResize = autoResize AutoResizeMultiplier = autoResizeMultiplier End Property AutoResize:Bool() Return _autoResize Setter (value:Bool) _autoResize = value End Property AutoResizeMultiplier:Float() Return _autoResizeMultiplier Setter (value:Float) _autoResizeMultiplier = value If _autoResizeMultiplier < 1.1 Then _autoResizeMultiplier = 1.1 End Property Capacity:UInt() Return _capacity Setter (value:UInt) If value >= _capacity _capacity = value Fill() Else _capacity = value For Local n := _objs.Length until _capacity Step - 1 _objs.Pop() Next Endif End Property Contents:Stack<T>() Return _objs End Method Put:Void(obj:T, forceAppend:Bool = False) If _objs.Length < _capacity _objs.Push(obj) Else If forceAppend _objs.Push(obj) _capacity += 1 Endif Endif End Method Get:T() If _objs.Empty If AutoResize Capacity *= AutoResizeMultiplier Else Return Null Endif Endif Return _objs.Pop() End End '-------------------- Class Obj Private Global IdCounter:UInt = 1 Field _id:UInt Public Method New() _id = IdCounter IdCounter += 1 End Method ToString:string() Return "ID: " + _id End Function PrintStack:Void(objs:Stack<Obj>) If objs = Null Then Return For Local obj := Eachin objs Print obj.ToString() Next End End '-------------------- Function Main:Void() Local pool:=New Pool<Obj>(5) Obj.PrintStack(pool.Contents) 'pool.Capacity = 15 'Obj.PrintStack(pool.Contents) Local active := New Stack<Obj> Print "~n------------" Print "ALLOCATION" Print "------------" Print "~nActive:" For Local n:= 1 To 6 Local obj := Cast<Obj>(pool.Get()) If (obj<>Null) active.Push(obj) Else Print "NULL" Endif Next Obj.PrintStack(active) Print "~nPooled:" Obj.PrintStack(pool.Contents) Print "~n------------" Print "FREEING" Print "------------" For Local n := 1 To 3 pool.Put(active.Pop(), True) Next Print "~nActive:" Obj.PrintStack(active) Print "~nPooled:" Obj.PrintStack(pool.Contents) End

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[crayon-5cba9b9e6230e135407959 inline="true" ] #import "<std>"   Using std.collections   '----   Class Pool<T>   Private Field _autoResize:Bool Field _autoResizeMultiplier:Float Field _capacity:UInt Field _objs:Stack<T> Method Fill:Void() For Local n:= _objs.Length Until _capacity 'A default constructor (New() without parameters) is required 'otherwise the compiler will raise the following  error: 'Can't find overload for 'new(...)' with argument types () _objs.Push(New T()) Next End   Public Method New(capacity:UInt = 10, autoResize:Bool = True, autoResizeMultiplier:Float = 2.0) _objs = New Stack<T> Capacity = capacity AutoResize = autoResize AutoResizeMultiplier = autoResizeMultiplier End   Property AutoResize:Bool() Return _autoResize Setter (value:Bool) _autoResize = value End   Property AutoResizeMultiplier:Float() Return _autoResizeMultiplier Setter (value:Float) _autoResizeMultiplier = value If _autoResizeMultiplier < 1.1 Then _autoResizeMultiplier = 1.1 End   Property Capacity:UInt() Return _capacity Setter (value:UInt) If value >= _capacity _capacity = value Fill() Else _capacity = value For Local n := _objs.Length until _capacity Step - 1 _objs.Pop() Next Endif End Property Contents:Stack<T>() Return _objs End Method Put:Void(obj:T, forceAppend:Bool = False) If _objs.Length < _capacity _objs.Push(obj) Else If forceAppend _objs.Push(obj) _capacity += 1 Endif Endif End Method Get:T() If _objs.Empty If AutoResize Capacity *= AutoResizeMultiplier Else Return Null Endif Endif Return _objs.Pop() End   End   '--------------------   Class Obj Private Global IdCounter:UInt = 1 Field _id:UInt Public Method New() _id = IdCounter IdCounter += 1 End Method ToString:string() Return "ID: " + _id End Function PrintStack:Void(objs:Stack<Obj>) If objs = Null Then Return For Local obj := Eachin objs Print obj.ToString() Next End End   '--------------------   Function Main:Void() Local pool:=New Pool<Obj>(5) Obj.PrintStack(pool.Contents)   'pool.Capacity = 15 'Obj.PrintStack(pool.Contents)   Local active := New Stack<Obj> Print "~n------------" Print "ALLOCATION" Print "------------"   Print "~nActive:" For Local n:= 1 To 6 Local obj := Cast<Obj>(pool.Get()) If (obj<>Null) active.Push(obj) Else Print "NULL" Endif Next Obj.PrintStack(active)   Print "~nPooled:"   Obj.PrintStack(pool.Contents)   Print "~n------------" Print "FREEING" Print "------------" For Local n := 1 To 3 pool.Put(active.Pop(), True) Next Print "~nActive:" Obj.PrintStack(active) Print "~nPooled:" Obj.PrintStack(pool.Contents)   End

[/crayon]

I do have another solution somewhere that makes use of objects that implement a “Pooleable” Interface. I’ll see if I can dig it up and post it as another example…

[impixiParticipant]

Here’s the other pooling technique I experimented with:

Monkey

[crayon-5cba9b9e6903a025171996 inline="true" ] #import "<std>" Using std.collections Interface iPoolable Field idx:Int '*** For TESTING only. Method ToString:String() '*** End Class ArrayPool Private Field _capacity:Int Field _objs:iPoolable[] Field _autoResize:Bool Field _autoResizeMultiplier:Float Field _creator:iPoolable() Field _idxAvailable:Int Public Method New(creator:iPoolable(), capacity:Int = 10, autoResize:bool = True, autoResizeMultiplier:Float = 2.0) AutoResize = autoResize AutoResizeMultiplier = autoResizeMultiplier Creator = creator Capacity = capacity _idxAvailable = 0 End Property AutoResize:Bool() Return _autoResize Setter (value:Bool) _autoResize = value End Property AutoResizeMultiplier:Float() Return _autoResizeMultiplier Setter (value:Float) If value <= 1.0 Then value = 1.1 _autoResizeMultiplier = value End Property Capacity:Int() Return _capacity Setter (value:Int) If value >= _capacity Local arr := New iPoolable[value] _objs.CopyTo(arr, 0, 0, _objs.Length) _objs = arr For Local i:= _capacity Until value _objs[i] = _creator() _objs[i].idx = i Next FindAvailableIdx() Else _objs = _objs.Slice(0, value) If _objs[value] = Null Then _idxAvailable = value Endif _capacity = value End Property Creator:Void(func:iPoolable()) If func = Null Then RuntimeError("Error: Poolable object creation function cannot be null.") _creator = func End Property Contents:iPoolable[]() Return _objs End Method FindAvailableIdx:Void() For Local i:Int = 0 Until _objs.Length If _objs[i] <> Null _idxAvailable = i Return Endif Next _idxAvailable = _capacity End Method Free:Void(obj:iPoolable) If obj = Null Then Return _idxAvailable -= 1 _objs[_idxAvailable] = obj End Method Allocate:iPoolable() If _idxAvailable >= _capacity If Not _autoResize Return Null Else Capacity *= _autoResizeMultiplier Endif Endif Local obj := _objs[_idxAvailable] _objs[_idxAvailable] = Null _idxAvailable += 1 Return obj End '*** For TESTING Method PrintAll:Void() Print "------" For Local obj := Eachin _objs If obj = Null Then Continue Print obj.ToString() + " -- IDX = " + obj.idx Next Print "------" End '*** End '--------------- Class Obj Implements iPoolable Private Global IdCounter:UInt = 1 Field _id:UInt Public Function Create:iPoolable() Return New Obj() End Method New() _id = IdCounter IdCounter += 1 End Method ToString:string() Return "ID: " + _id End '*** For TESTING only. Function PrintStack:Void(stack:Stack<Obj>) If stack = Null Then Return If stack.Empty Then Return For Local obj:= Eachin stack Print obj.ToString() Next End '*** End '--------------- Function Main:Void() Local pool:=New ArrayPool(Obj.Create, 5, True) Local active := New Stack<Obj> Print "~n------------" Print "ALLOCATION" Print "------------" Print "~nActive:" For Local n:= 1 To 9 Local obj := Cast<Obj>(pool.Allocate()) If (obj<>Null) active.Push(obj) Else Print "NULL" Endif Next Obj.PrintStack(active) Print "~nPooled:" pool.PrintAll() Print "~n------------" Print "FREE" Print "------------" For Local n := 1 To 5 pool.Free(active.Pop()) Next Print "~nActive:" Obj.PrintStack(active) Print "~nPooled:" pool.PrintAll() Print "~nAllocate again" For Local n:= 1 To 4 Local obj := Cast<Obj>(pool.Allocate()) If (obj<>Null) active.Push(obj) Else Print "NULL" Endif Next Print "~nActive:" Obj.PrintStack(active) Print "~nPooled:" pool.PrintAll() End

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[crayon-5cba9b9e6903a025171996 inline="true" ] #import "<std>"   Using std.collections   Interface iPoolable Field idx:Int '*** For TESTING only. Method ToString:String() '***   End   Class ArrayPool   Private Field _capacity:Int Field _objs:iPoolable[] Field _autoResize:Bool Field _autoResizeMultiplier:Float   Field _creator:iPoolable()   Field _idxAvailable:Int   Public Method New(creator:iPoolable(), capacity:Int = 10, autoResize:bool = True, autoResizeMultiplier:Float = 2.0) AutoResize = autoResize AutoResizeMultiplier = autoResizeMultiplier Creator = creator Capacity = capacity _idxAvailable = 0 End Property AutoResize:Bool() Return _autoResize Setter (value:Bool) _autoResize = value End Property AutoResizeMultiplier:Float() Return _autoResizeMultiplier Setter (value:Float) If value <= 1.0 Then value = 1.1 _autoResizeMultiplier = value End Property Capacity:Int() Return _capacity Setter (value:Int) If value >= _capacity Local arr := New iPoolable[value] _objs.CopyTo(arr, 0, 0, _objs.Length) _objs = arr For Local i:= _capacity Until value _objs[i] = _creator() _objs[i].idx = i Next FindAvailableIdx() Else _objs = _objs.Slice(0, value) If _objs[value] = Null Then _idxAvailable = value Endif _capacity = value End Property Creator:Void(func:iPoolable()) If func = Null Then RuntimeError("Error: Poolable object creation function cannot be null.") _creator = func End Property Contents:iPoolable[]() Return _objs End Method FindAvailableIdx:Void() For Local i:Int = 0 Until _objs.Length If _objs[i] <> Null _idxAvailable = i Return Endif Next _idxAvailable = _capacity End Method Free:Void(obj:iPoolable) If obj = Null Then Return _idxAvailable -= 1 _objs[_idxAvailable] = obj End Method Allocate:iPoolable() If _idxAvailable >= _capacity If Not _autoResize Return Null Else Capacity *= _autoResizeMultiplier Endif Endif Local obj := _objs[_idxAvailable] _objs[_idxAvailable] = Null _idxAvailable += 1   Return obj End   '*** For TESTING Method PrintAll:Void() Print "------" For Local obj := Eachin _objs If obj = Null Then Continue Print obj.ToString() + " -- IDX = " + obj.idx Next Print "------" End '***   End   '---------------   Class Obj Implements iPoolable   Private Global IdCounter:UInt = 1 Field _id:UInt Public Function Create:iPoolable() Return New Obj() End Method New() _id = IdCounter IdCounter += 1 End Method ToString:string() Return "ID: " + _id End '*** For TESTING only. Function PrintStack:Void(stack:Stack<Obj>) If stack = Null Then Return If stack.Empty Then Return For Local obj:= Eachin stack Print obj.ToString() Next End '***   End   '---------------   Function Main:Void()   Local pool:=New ArrayPool(Obj.Create, 5, True)   Local active := New Stack<Obj> Print "~n------------" Print "ALLOCATION" Print "------------"   Print "~nActive:" For Local n:= 1 To 9 Local obj := Cast<Obj>(pool.Allocate()) If (obj<>Null) active.Push(obj) Else Print "NULL" Endif Next Obj.PrintStack(active)   Print "~nPooled:"   pool.PrintAll()   Print "~n------------" Print "FREE" Print "------------" For Local n := 1 To 5 pool.Free(active.Pop()) Next Print "~nActive:" Obj.PrintStack(active) Print "~nPooled:" pool.PrintAll()   Print "~nAllocate again"   For Local n:= 1 To 4 Local obj := Cast<Obj>(pool.Allocate()) If (obj<>Null) active.Push(obj) Else Print "NULL" Endif Next Print "~nActive:"   Obj.PrintStack(active)   Print "~nPooled:"   pool.PrintAll()   End

[/crayon]

Objects to be pooled must implement the iPoolable Interface. The pool also requires a “creator function” (basically a constructor replacement).

This technique affords greater flexibility though at a cost of greater abstraction.

I used an array instead of a stack for performance testing reasons – surprisingly there was no performance benefit. Maybe I should reimplement it with a Stack…

[ivan.velhoParticipant]

My problem is free memory in time the destruction method is called, same problem every garbage collector has.
But if you want to be faster than a constructor method, I suggest you to create a pool of objects with a recycle method, this method must do the same as a constructor but it will do on an allocated object.
This is the reason you can’t be faster with any other strategy.

[ivan.velhoParticipant]

The limitation of this method is the pool must contain only objects of the same class.
You cannot do up cast as down cast.

[JesseParticipant]

I created a simple generic pool class. I think t’s as fast as it can get. it has no limitation on size and has a return to pool function. The only requirements is that all objects to be stored or created must extend StoreObject class:

Monkey

[crayon-5cba9b9e74894284776390 inline="true" ] '******************************************************* '* Pool * '******************************************************* Class Store<T> Field last:T Field total:Int Method New() End Method Method New(count:Int) Fill(count) End Method Method Fill:Void(total:Int) For Local i:Int = 0 Until total Local c:T = New T c._pred = last last = c Next Self.total += total End Method Method Count:Int() Return total End Method Method GetItem:T() If last Local c:T = last last = Cast<T>(last._pred) c._pred = Null total -= 1 Return c Endif Return New T End Method Method ReturnItem:Void(obj:T) obj._succ = Null obj._pred = last last = obj total += 1 End Method End Class Class StoreObject Abstract Field _pred:StoreObject Method New() End method End Class

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[crayon-5cba9b9e74894284776390 inline="true" ] '******************************************************* '* Pool    * '*******************************************************   Class Store<T> Field last:T Field total:Int Method New() End Method Method New(count:Int) Fill(count) End Method   Method Fill:Void(total:Int) For Local i:Int = 0 Until total Local c:T = New T c._pred = last last = c Next Self.total += total End Method Method Count:Int() Return total End Method Method GetItem:T() If last Local c:T = last last = Cast<T>(last._pred) c._pred = Null total -= 1 Return c Endif Return New T End Method Method ReturnItem:Void(obj:T) obj._succ = Null obj._pred = last last = obj total += 1 End Method End Class   Class StoreObject Abstract Field _pred:StoreObject Method New() End method End Class

[/crayon]

[ivan.velhoParticipant]

I think I could use another approach to the problem.

I can use  SDL/libc to allocate SDL pixmaps.

These are the major resources , I must study this solution . I believe monkey2 is based on SDL and the low level SDL/libc were provided to give a low level control.

I think I must study the integration and figure out how to do this .

Thanks guys for the help.

[ivan.velhoParticipant]

There is no problem:

Namespace std.graphics

#rem monkeydoc Pixmaps allow you to store and manipulate rectangular blocks of pixel data.

A pixmap contains a block of memory used to store a rectangular array of pixels.

#end
Class Pixmap

#rem monkeydoc @hidden
#end
Field OnDiscarded:Void()

#rem monkeydoc Creates a new pixmap.

@param width The width of the pixmap in pixels.

@param height The height of the pixmap in pixels.

@param format The pixmap format.

@param data A pointer to the pixmap data.

@param pitch The pitch of the data.

#end
Method New( width:Int,height:Int,format:PixelFormat=PixelFormat.RGBA32 )

Local depth:=PixelFormatDepth( format )
Local pitch:=width*depth
Local data:=Cast<UByte Ptr>( libc.malloc( pitch*height ) )

_width=width
_height=height
_format=format
_depth=depth
_data=data
_pitch=pitch
OnDiscarded=Lambda()
libc.free( data )
End
End

 

Pixmap calls libc.free(data)

I believe it is not in garbage collector at all.

I believe Mark used the approach from libgdx (LWJGL)and allocate and delete resources out of garbage collector, through native method.

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