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These are the results after running the program about twenty times. I ran the program on the same machine with the same other programs running and recorded the figures from the process tab in task...

Have to hand this in by 10pm (GMT). Thanks for all your help if you don't get back to me by then. Much appreciated, thanks again,

funkylunch.

ok well how about this,

how can i re-write the program so it only uses virtual memory:
by using the virtual alloc function?
Then maybe I could work out the answer myself.

What do you think?
...

salem,

I know this is bumping my threads, but i really want to know the answer. Are you not replying because

a.) You still think it is a stupid question?

...

fordy,

can u help me with my other problem: memory access time?

fordy, can u help me with my memory access time problem too?
am i not allowed to post messages like this?

do you mean "when" instead of "unless"?

why would i not want to burden my heap with something?

why would i want to allocate a block at a specific point in my usermode address space?

Why...

that still doesn't explain when it would be better to use virtual alloc. Is virtual alloc pointless?

Can you explain when it would be more appropriate to use
virtual alloc rahter than malloc in laymans terms?

I looked in the MSDN library, but it may as well be in Swahili.

thanks for all your...

so,

i press the use button and it writes something to a VM block. Exactly what is it writing? Just 1's? And, how much each time i press it? 64Kb or as much as i have commited?

the last line line (the most important one!) should read

67108.864, 66392, 3716, 5.59706, 433, 715,1.65

My table got messed up when i posted it, here is a version without any spaces:

Array, Max mem used, VM used, % mem =VM, R by R time,
C by C time, C by C : R by R ratio:::::

0.256, 568, 168,...

Actually,

Hold on a minute, it still doesn't make sense. Look at my table of results:


Array Max VM % mem Row col ratio
...

ok thanks

thats great,

when would it be a good idea to use virtual Alloc instead of malloc? could you give me some "real" examples?

Salem,

I still cant unerstand why when you run this program it is always quicker to access the memory row by row. You said earlier that if it is neither cached or paged then it makes no...

anyone got any ideas? thanks,

Hi,

I think there is a way to run the whole program in virtual memory. Does anyone know how I would have to change the above code to acheive this?

I think it would involve the virtual alloc...

// VMStatsDlg.cpp : implementation file
//

#include "stdafx.h"
#include "VMStats.h"
#include "VMStatsDlg.h"

#include <winbase.h> // For GlobalMemoryStatus and MEMORYSTATUS

#ifdef _DEBUG

Right, so how can i modify this program so it only uses virtual memory? alternatively how else can i prove that

1. Accessing virtual memory column by column is slower than row by row.

2. These...

oh, and what is moot?

ok, so i need to post the code in the message somewhow. I looked in the FAQ but found nothing about posting visual c code. Please could someone tell me how to post the code as text here without...

ok,

sorry about the code. So can I re-write the program (rowcol.c, in my first thread which everyone was too scared to download) so it only uses virtual memory? isn't there a function called:
...

Thanks that is great. Are you sure it makes no difference to access times in terms of main memory if accessed row by row or column by column? I would like to check that using this simple visual c...

i am not sure but I think it is quicker to acccess virtual memory
column by column as opposed to row by row.

Real memory displays opposite properties.

Can anyone explain why this is so? Or...