Page file usage

[Guest]

I have 2gb of Ram installed in my system. I am using xppro. When I am running
apps like my newsreader, my PF Usage, according to my Taskmanager, at times
will go over 1 Gb { if I have other programs open too} while saying I have
1.4 Gb Ram available. Is this right?

 

[David Candy]

Yes. It's not referring only to the page file. Open programs become used pagefiles. More programs open more of the pagefile in use.

 

[Guest]

I dont think its right.
when 1.4 GB is free why should it swap out your process...
I also have similar problem....

is there any way we can customize the memory management for a particular
process.

Say i dont want MATLAB or paintshop process to be swapped out to reduce the
page fault, is hter any way to do that.

"ivenholt" ने लिखा:

 

[Gerry Cornell]

Task Manager does not record Page File Usage. It record allocations of the
page file which may or may not be used.
http://aumha.org/win5/a/xpvm.htm

You may check on pagefile (virtual memory) usage with
Page File Monitor for XP:
http://www.dougknox.com/

Make sure you study the readme.txt file carefully to ensure
you get the utility to work as it should.

This utility demonstrates the overall amount of the pagefile
in use. It does not say which application is using it.



--

Hope this helps.

Gerry
~~~~
FCA
Stourport, England

Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[Guest]

Hi David,
i am a beginner and dint understand your reply completely, could
you please explain in more detail.

 

[David Candy]

You don't understand anything. And the code segments of an exe will always be swapped out because it would have to delete the exe file to not swap it. If matlab needs memory windows will give it to it. Matlab can give and probably does give guidelines to Windows (most programs only advise they need 256K to 512K). Remember things get swapped to memory first. This is a soft fault.

 

[David Candy]

Programs when loaded are called a module. Program files have sections. Data, Code, stack, resources. Many never change if on disk or in memory. So they never get written to disk as it's already on disk in the exe file. If needed to be swapped it's just dumped from memory and reloaded from the file as needed.

Only things that change get written to a swap file. This is data, either a word doc or data a program needs to work. However it goes to a not required status, then if under stress written out as needed or if not stressed and the computer has nothing to do written out speculatively but stays in memory.

Exe files (and other files but they don't count for swap) are also in the cache. So they are usually read from there.

Windows tunes each apps memory about once a second (I think) by stealing a page of memory from the program. If the program then issues a page fault for it, it will be given back - note it's in memory anyway.

Minimised programs are given preference to being swapped out.

Swapping is far quicker than normal file operations. More and more programs use the same technique for data files now too. These are known as memory mapped files.

Big programs also have access to their own virtual memory manager that they control.

 

[Ron Martell]

I have 2gb of Ram installed in my system. I am using xppro. When I am running
apps like my newsreader, my PF Usage, according to my Taskmanager, at times
will go over 1 Gb { if I have other programs open too} while saying I have
1.4 Gb Ram available. Is this right?

A large portion if not all of what you are seeing in Task Manager is
"phanton" Page File Usage resulting from the unused portions of memory
allocation requests.

What happens is that memory allocation requests issued by Windows
components, device drivers, and application programs invariably ask
for memory allocations that are larger than what is actually needed
under normal circumstances.

By design, Windows must identify memory address space for all of the
requested memory, even the unused portions. So what happens is that
Windows allocates RAM only to those portions that are actually used
and maps the unused portions to locations in the pagefile. Note that
this mapping of unused memory requests to the pagefile does not
require any actual disk activity - all that is needed is to make
entries in the memory mapping tables maintained by the CPU.

Unfortunately there is no ready way of determing actual paging file
usage provided with Windows XP - it does not have an equivalent to the
'Memory Manager - Swap File In Use" reporting provided by the System
Monitor utility in Windows 95/98/Me.

There is a free utility that you can download and run which will
provide this information for you. It was written by MVP Bill James and
you can get if from
http://www.dougknox.com/xp/utils/xp_pagefilemon.htm or from
http://billsway.com/notes_public/WinXP_Tweaks/


For example, on my own system at this moment with 512 mb of RAM Task
Manager reports PF Usage as 358 mb. Bill's utility tells me that
there is actually 34 mb of active memory content in the pagefile. The
difference 358 - 34 = 324 mb represents the total of unused portiosn
of memory allocation requests on my system at this moment.


Hope this explains the situation.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."

 

[Guest]

Thanks for all of the replies guys...I think I am starting to understand
what is going on.