XP PageFileMon

  • Thread starter Thread starter Randy Harris
  • Start date Start date
R

Randy Harris

I've been attempting to use the XP_PageFileMon utility developed by Bill
James but seem to be getting results that don't make much sense. I set it
up to write to a log file on each system shutdown but the log shows numbers
that are nowhere close to what the XP task manager reports. For example,
the task manager reported 161MB in use (as did AIDA32), but XP_PageFileMon
reported 6MB at the same time. Anyone know if that tool is really that
inaccurate, or am I doing something wrong?
 
from the wonderful said:
I've been attempting to use the XP_PageFileMon utility developed by Bill
James but seem to be getting results that don't make much sense. I set it
up to write to a log file on each system shutdown but the log shows numbers
that are nowhere close to what the XP task manager reports. For example,
the task manager reported 161MB in use (as did AIDA32), but XP_PageFileMon
reported 6MB at the same time. Anyone know if that tool is really that
inaccurate, or am I doing something wrong?
Click to expand...

That's exactly what you'd expect to see. Bill's utility reports the PF
that is actually in use - been written to. Task manager and Aida32 both
report PF that has been 'committed'. Some program asks for 1GB of
memory, with no intent to use it any time soon (or ever) XP will
'commit' 1GB of Page File to hold it (assuming max page file is big
enough to accommodate it). It won't actually write anything to the PF,
since the memory has not been used. If the program actually tries to use
some, XP will allocate RAM for the 'in use' part (and de-commit PF)
until/unless all RAM is used up - at that point 'something' will
actually have to get written to PF, using the normal paging algorithm
(Least Recently Used, or 'LRU', presumably).

On a 'normal' XP system there is 100-150MB of stuff 'committed' to PF,
but never actually written .. you're seeing 155MB, so you are right
around the normal number.
 
It's the task manager does not report page file usage properly! That's why
Bill James wrote his little script!
 
Randy said:
I've been attempting to use the XP_PageFileMon utility developed by Bill
James but seem to be getting results that don't make much sense. I set it
up to write to a log file on each system shutdown but the log shows numbers
that are nowhere close to what the XP task manager reports. For example,
the task manager reported 161MB in use (as did AIDA32), but XP_PageFileMon
reported 6MB at the same time.a
Click to expand...

And it is PageFileMon that is telling you the answer that matters -
pages that have actually had something written to them. It is just
because Task Monitor is grossly misleading that Bill developed the tool.

You can confirm by setting the initial size of Page file to say 30MB (I
would only suggest such a really low value for testing). And then see
how values compare with the actual size of pagefile.sys as shown in
explorer. (have Folder Options - View set to show Hidden files, and
*not* Hide Protected mode ones)

Read up background at www.aumha.org/win5/a/xpvm.htm
 
I didn't see this thread until now, but I see Alex and GSV have answered
your questions. I will just add that your concerns about the difference in
reported size are not unusual. I get several emails a week along the same
line.

--
Bill James
Microsoft MVP·DTS

Win9x VBScript Utilities » www.billsway.com/vbspage/
Windows Tweaks & Tips » www.billsway.com/notes_public/
 
Thanks Bill. And thanks to all the other kind souls who took the time to
explain this matter. (I was indeed perplexed)
--
Randy Harris


Bill James said:
I didn't see this thread until now, but I see Alex and GSV have answered
your questions. I will just add that your concerns about the difference in
reported size are not unusual. I get several emails a week along the same
line.

--
Bill James
Microsoft MVP·DTS

Win9x VBScript Utilities » www.billsway.com/vbspage/
Windows Tweaks & Tips » www.billsway.com/notes_public/
Click to expand...
 
Back
Top