cbNKPagingPoolSize

Other versions of this page are also available for the following:
Windows Mobile Not SupportedWindows Embedded CE Supported
8/28/2008

This variable enables OEMs to limit memory used for paging read-only code or map files by setting the variable to the maximum memory allowed.

This variable is deprecated in Windows Embedded CE in favor of IOCTL_HAL_GET_POOL_PARAMETERS.


DWORD cbNKPagingPoolSize;

None.

The paging pool is a reserved block of RAM that for holding pages of code. If the paging pool is not enabled, the entire RAM on the device is available for paging, which can drastically increase RAM usage. Enabling the paging pool sets aside a limited amount of RAM for paging. The higher the paging pool size, the more RAM is available for paging. This results in fewer page faults, since more code can be held in the paging pool. It is important to determine the right balance between RAM usage for paging pool and paging performance. The following list shows examples of some factors that affect the optimum paging pool size:

  • Attributes of OEM components, such as device drivers. Examples of attributes are total size and pageability.
  • Total available RAM.
  • Processor speed.
  • Flash technology, for example, NAND or NOR.

To determine the optimum paging pool size, collect performance data for various paging pool sizes.

The following table shows an example of data that was collected for a reference Windows Mobile 6 Standard platform:

Paging pool size 3.0 MB 3.5 MB 4 .0 MB 4.5 MB 5.0 MB 6.0 MB

Boot time

38.1 seconds

37.4 seconds

34.6 seconds

31.2 seconds

29.7 seconds

28.4 seconds

Inbox launch

3.31 seconds

3.20 seconds

2.77 seconds

2.66 seconds

2.59 seconds

2.45 seconds

Contacts launch

1.72 seconds

1.62 seconds

1.41 seconds

1.20 seconds

1.16 seconds

1.15 seconds

You can graph the performance and paging pool size for each scenario to determine the paging pool size that provides a good balance between RAM used for the paging pool and performance. For the above table, 4.5 MB is the optimum size.

HeaderDeveloper Implemented
Windows Embedded CEWindows CE 5.0 and later

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