Re: Question about paging rate

How much physical RAM do you have? Maybe you could improve things by adding more, say, doubling it? Note that the paging rate you mention is within a factor of 2 of what a typical disk can do. 7200 RPM is 120 RPS so that is approximately the max number of blocks per second you can get. (Yah, I know sometimes you can pick up more than one block per rev.)


Stuart Rogers wrote:
None of the memory indicators for this app are increasing so there does not appear to be a memory leak. The Cache values are pretty static as well

It is not a database app either, however it does manipulate quite a lot of data and files, it collects data from a weather station. So I guess it is probably the OS doing its thing with data going to disk for these files.

One thing I do know about this app is that it is coded using Delphi so I dont know if that is likely to cause it to behave differently with regards to memory and paging?

Stuart

"Steve Duff [MVP]" <ergodic@xxxxxxxxxxxxxxxxxxx> wrote in
news:umupoYTlFHA.3568@xxxxxxxxxxxxxxxxxxxx: 


A request for new virtual address space or a fresh data page
will generate what is termed a demand-zero fault. This takes
a page of memory and zeros it for the application to use.
While technically a fault (because it is initiated by a reference to
non-existant memory in the app's address space), it does not in and of
itself produce disk activity - at least until and if it is paged out.

An application that is doing this and continuously growing in
virtual address size is the classic "memory leak" (or just badly
written). If it is doing this and not growing endlessly then it may
be doing process-shared memory or deallocations/reallocations
or using AWE or one of the dozens of other possible memory
management strategies.

Another source of soft faults is when a page is moved back
from the standby list (on its way out the door so to speak), back
in to the application's memory working set. This is just
a page mapping operation and no disk activity is generated.
These are so-called transition faults and the rate is really
dependent on what else is running on the server (especially
SQL Server and Exchange which both have quite highly
specialized internal memory mangement of their own.)

Also, file operations are usually through virtual memory section
mappings internally in the o/s, and so the fault rate counts these
cache misses. Again this is not an indication of an application
problem, it is just the system doing what it is supposed to. If your
application is file-intensive (say a database app), this may be
the source.

And if the app needs to run with "lock pages in physical memory"
rights it is probably safe to assume it knows what it is doing. You
can use perfmon to see some of the VM indicators, though some
things like AWE, shared and large pages are not counted in
some of the indicators.

The best thing to do of course is ask the developers.

Steve Duff, MCSE, MVP
Ergodic Systems, Inc.

"Stuart Rogers" <me@xxxxxxxxxxx> wrote in message
news:Xns96A3BF688A987stuartfreenews@xxxxxxxxxxxxxx

I run an application which I feel is paging too much. The PC is
dedicated to this one application and mysql. The app in question page faults at
a rate of between 30--70/second averaging around 55/second, however
the system pages/second is less than 0.1/second so these faults are
not causing hard page faults. Should I be concerned about this, it
seems to me that since this is the only app or service with any
apreciable paging that this could be a design problem within the app
itself. However I have been unable to find out what is actually
causing the page faults. Can any one suggest a way to trace the
actual storage causing the fault I could then try and find out what
this memory is used for within the app. 
.

Relevant Pages

  • Re: Question about paging rate
    ... a page of memory and zeros it for the application to use. ... These are so-called transition faults and the rate is really ... And if the app needs to run with "lock pages in physical memory" ... > to find out what is actually causing the page faults. ...
    (microsoft.public.win2000.general)
  • Re: Question about paging rate
    ... None of the memory indicators for this app are increasing so there does ... > These are so-called transition faults and the rate is really ...
    (microsoft.public.win2000.general)
  • Re: Question about paging rate
    ... These are not hard page faults, they do not for the vast majority end up ... >> None of the memory indicators for this app are increasing so there ... >> does not appear to be a memory leak. ...
    (microsoft.public.win2000.general)
  • Re: how do you use pfmon.exe
    ... Pfmon displays a list of hard page faults in the command window while the ... might want to rerun Pfmon while limiting the amount of memory to see how your ... LeakyApp is a GUI tool included on the Windows 2000 Resource Kit CD. ...
    (microsoft.public.win2000.cmdprompt.admin)
  • Re: How to set up a Linux machine that occupies the minimum memory footprint ?
    ... Of course, if you use 8GB of RAM, or more precisely if you ... Are you saying that if I have a 4GB RAM memory, ... Linux will somehow "know" that it doesn't have ... You've said in another message that your app is ...
    (comp.os.linux.setup)