[THIN] Re: High Page Swaps

  • From: "Luchette, Jon" <JLuchette@xxxxxxxxxxxxxxx>
  • To: <thin@xxxxxxxxxxxxx>
  • Date: Fri, 22 Sep 2006 14:52:00 -0400

...excellent.  thanks Tim!
Jon Luchette

Emerson Hospital
Technology Specialist III
Work: 978-287-3369
Cell:  978-360-1379




From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On
Behalf Of Tim Mangan
Sent: Friday, September 22, 2006 1:04 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: High Page Swaps



First, you should do the following to confirm if this really is a
performance issue.  Page swapping occurs when overall system memory
usage gets high.  But not all page swapping is a performance issue.  A
page swap is counted any time a process tries to access a memory page
that is not in its working set.  This might mean that the page was
swapped out to disk and is no longer in memory and has to be read in
"on-demand" (called a hard page fault).  It might also be a soft page
fault, where the memory has been removed from the working set as part of
the page-out procedure but is still present on a virtual memory page.
With a soft page fault the memory is immediately restored to the working
set with very, very, little overhead.


One should look at the "pages in" counter from the OS to determine the
hard-fault rather than the "page fault" counter which includes both hard
and soft faults.  You can confirm this using whatever management tool
you have handy, including the "performance monitor" that is included in
the OS.  Only if the "pages in" counter is high should you consider it a
performance issue worth concerning yourself with.  In that case you want
to look for processes with high memory use, especially one that keeps
growing over time which may indicate a memory leak bug.


Tim Mangan


From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On
Behalf Of Luchette, Jon
Sent: Thursday, September 21, 2006 10:20 AM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] High Page Swaps


Hello -


I am using the advanced load monitor on MF XP FR3 sp4 running win 2k3
sp1 boxes on BL35p hardware booting from SAN.  Every once in a while I
notice that the Page Swaps Rule is maxed out 100% on one or two of my
servers when I check within the CMC.   How would I track down the
culprit to try and stop this from reoccurring?




Jon Luchette 

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