OpenEuphoria

Re: Memory usage on Win32: Euphoria usage vs. what Task Manager displays

• Posted by DerekParnell (admin) Jul 31, 2009
• 952 views

I'm using Windows XP too.

I stand by my assertion that memory released by reducing the size a sequence is made available for reuse. If the amount of memory released is larger than the system page size, that memory can be reused by other applications.

I'm using two measurements to confirm this. Using the Windows system monitor, I'm looking at the Available Physical Memory (APM) and the "Mem Usage" (MU) for the eui.exe process.

As memory is allocated and assigned to the 'x' object, APM is decreasing and MU is increasing. When the 'x' object is assigned 0, APM is increases to (almost) the initial value, and MU decreases to (almost) its initial value. The residual amount I think is associated with the minimum allocation size for RAM (usually 4K or system page size).

Also, the time difference between concatenating and pre-allocating is negliable.

Here is my pre-allocation version

  
clear_screen()  
integer c 
object ch 
object x  
sequence t 
atom e 
c = 1 
puts(1, "Begin?\n") 
ch = gets(0) 
 
t = repeat(0,1000) 
x = repeat(0, 50*500)  
puts(1, "Pre-allocation done\n") 
ch = gets(0) 
puts(1, "Allocating ...\n") 
 
e = time() 
 
for i = 1 to 50 do -- adjust if it grabs too much memory for your system  
	? i  
	for j = 1 to 500 do  
 		for q = 1 to 1000 do 
 			t[q] = rand(1000) / rand(1000) 
 		end for 
		x[c] = t 
		c += 1 
	end for  
end for  
 
? time() - e  
puts(1, "End of allocation\n") 
ch = gets(0)  
x = 0 
puts(1, "X deferenced\n") 
ch = gets(0) 

I don't think so.

What are you using to measure this? I'm not seeing this effect at all.