PerfMon: High Number of Pages/sec Not Necessarily Low Memory

 Last reviewed: October 2, 1997
Article ID: Q139609
The information in this article applies to:
  • Microsoft Windows NT Workstation version 3.51
  • Microsoft Windows NT Server version 3.51

SUMMARY

When using Performance Monitor, you might encounter high Memory: Pages/sec counter values that are not related to either paging file activity or cache activity. These high values may instead be caused by the an application sequentially reading a memory mapped file.

MORE INFORMATION

The following information is from the Performance Monitor counter definition information for the Memory Pages/sec counter. 

   Pages/sec is the number of pages read from the disk or written to the
   disk to resolve memory references to pages that were not in memory at
   the time of the reference. This is the sum of Pages Input/sec and Pages
   Output/sec. This counter includes paging traffic on behalf of the
   system Cache to access file data for applications. This is the primary
   counter to observe if you are concerned about excessive memory pressure
   (that is, thrashing), and the excessive paging that may result. This
   counter, however, also accounts for such activity as the sequential
   reading of memory mapped files, whether cached or not. The typical
   indication of this is when you see high number of Memory: Pages/sec, a
   "normal" (average, relative to the system being monitored) or high
   number of Memory: Available Bytes, and a normal or small amount of
   Paging File: % Usage. In the case of a non-cached memory mapped file,
   you also see normal or low cache (cache fault) activity.
As seen from the above information, a high number of Memory: Pages/sec is not necessarily indicative of memory pressure or a Performance Monitor reporting error. It is necessary to monitor other counters, such as those mentioned above, to get the complete picture of what is happening in your particular case.

KBCategory: kbtool
KBSubcategory: ntutil ntconfig
Additional reference words: 3.51 prodnt pages per second percent
Keywords : ntconfig ntutil kbtool
Version : 3.51
Platform : WINDOWS

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Last reviewed: October 2, 1997
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