The automatic memory management of Blitzmax

BlitzMax Forums/BlitzMax Programming/The automatic memory management of Blitzmax

ohahaha

(Posted 2006) [#1]

hello
I'm making 2D physics engine with Blitzmax.
But, it is too slow to use "type vector2d" made with blitzmax.
The task that numerous vectors are generated and destroyed for a loop is too slow.
I think that this task is slower than another task with C++ by 100 times.
The automatic memory management of blitzmax is very useful, but slow for this kind of task.
I tried to use not "user defined type" but combination of array ptr. and functions,
but array is processed like "user defined type" too.
I'd like to use data structure constructed by 2 float number.
Can I make directly referenced struct in Bmax? I don't care if it is in OOP or not.
The source below is for test. The elapsed times to process this are about 0ms in C++, and 56ms in Bmax. Oh my god.

--------------------------------- c++ source ------------------------------------------

#include <iostream>
#include <ctime>
#include <conio.h>

class Vector {
public:
float x;
float y;

Vector(void);
Vector(float xi, float yi);
};

inline Vector::Vector (void)
{
x=0;
y=0;
}

inline Vector::Vector(float xi, float yi)
{
x=xi;
y=yi;
}

inline Vector operator+(Vector u, Vector v)
{
return Vector(u.x + v.x, u.y + v.y);
}

int main()
{
int const ITERATIONS = 100000;

long t = std::clock();

int loop;
Vector A = Vector(3,3);
Vector B = Vector(2,5);
Vector C = Vector (0,0);

for (loop = 0 ; loop < ITERATIONS ; loop++ )
{
Vector A = Vector(1,2);
Vector B = Vector(3,4);
Vector C ;
C=A+B;

}

t = std::clock() - t;

std::cout << ITERATIONS << " iterations took " << t << " millisecs.\n";

getch();

return 0;
}

------------------------------BMAX source------------------------------------------

Type tVec
Field x : Float
Field y : Float

Method add : tvec( _v : tvec)
Local v : tVec = New tvec
v.x=self.x+_v.x
v.y=self.y+_v.y
Return v
EndMethod

Function create : tvec (_x#=0.0,_y#=0.0)
Local v: tvec = New tvec
v.x=_x
v.y=_y
Return v
EndFunction

EndType

Const ITERATIONS = 100000

Local t = MilliSecs()

For Local i = 0 To ITERATIONS
Local va: tvec = tvec.create(3,3)
Local vb : tvec = tvec.create(3 , 4)
Local vc : tvec
vc = va.add(vb)
Next

Print ITERATIONS + " iterations took " + (MilliSecs() - t) +" millisecs."

Gabriel

(Posted 2006) [#2]

Why do you even need to create and destroy numerous instances every frame? Just creating or just destroying I could see, but if you're doing both, why don't you just pool and reuse them?

N	(Posted 2006) [#3]

What that guy over there said.

E.g.,

Strict

Type Vector
    Field x#, y#
End Type

Const VCACHE_INIT%=256
Global vectorUsed@[VCACHE_INIT]
memset_(vectorUsed,2,VCACHE_INIT)
Global vectorCache:Vector[VCACHE_INIT]
For Local i:Int = 0 To vectorCache.Length-1
    vectorCache[i] = New Vector
Next

Function GetVector:Vector( )
    For Local i:Int = 0 To vectorCache.Length-1
        If vectorUsed[i] = 2 Then
            vectorUsed[i] = 3
            Return vectorCache[i]
        EndIf
    Next
    Local from% = vectorCache.Length
    vectorCache = vectorCache[..from*2]
    vectorUsed = vectorUsed[..from*2]
    memset_( Varptr vectorUsed[from+1], 2, from )
    vectorUsed[from]=3
    For Local i:Int = from To vectorCache.Length-1
        vectorCache[i] = New Vector
    Next
    Return vectorCache[from]
End Function

Function FreeVector( vec:Vector )
    For Local i:Int = 0 To vectorCache.Length-1
        If vec = vectorCache[i] Then
            vectorUsed[i] = 2
            Return
        EndIf
    Next
End Function

Robert Cummings

(Posted 2006) [#4]

Perhaps more optimisation can be done by Mark?

Whats the perfomance when you turn on manual garbage collection?

ohahaha

(Posted 2006) [#5]

Const ITERATIONS = 100000
GCSetMode(2)
Local t = MilliSecs()
For Local i = 0 To ITERATIONS
Local va : tvec= vec(3 , 3)
Local vb :tvec = vec(2 , 5)
Local vc:tvec=va.add(vb)
GCCollect()
Next

Print MilliSecs() - t

100000 iterations took 119 millisecs.

--------------------------------------------------

For Local i = 0 To ITERATIONS
Local va : tvec= vec(3 , 3)
Local vb :tvec = vec(2 , 5)
Local vc:tvec=va.add(vb)
Next
GCCollect()

100000 iterations took 548 millisecs.

-_-;

N	(Posted 2006) [#6]

Put GCCollect at the beginning of the loop and tell us what that does.

ohahaha

(Posted 2006) [#7]

Thx, Noel.
But, It is too complicated for a wide use.
And in some intances, it's slower than using new method.

ohahaha

(Posted 2006) [#8]

I put Gccollect at the bigging of the loop.
100000 iterations took 123 millisecs.
no changes.