Microsoft KB Archive/121594

= Tasking Option Affects Server Service Priority =

Article ID: 121594

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Server 3.5

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This article was previously published under Q121594



3.10 3.50

WINDOWS

kbnetwork



SUMMARY
Process and threads in Windows NT run at a variety of priorities. Higher priority processes get more CPU time. The Windows NT server service priority is tied to the priority of the active foreground process. When tuning the performance of your system, it is important to understand the relationship between the server service priority and the foreground process priority.

By default, the server service priority is the same as the foreground process priority. Changing the Tasking option in the System applet of the Control Panel will affect the server service priority.

In addition, it is possible to change the relationship between the foreground and server priority through a Registry parameter.



MORE INFORMATION
In order to change the priority of all server threads in relation to the base priority of the foreground process, you can configure it through the Windows NT Registry.

NOTE: Higher priority can give better server performance at the cost of local responsiveness. Lower priority balances server needs with the needs of other processes on the system.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

 Start Registry Editor (REGEDT32.EXE) and go to the following subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services \LanmanServer\Parameters From the Edit menu, choose Add Value.  Enter the following values:

    Value Name: ThreadPriority Data Type: REG_DWORD Decimal:

Decimal Description ---     0      Process running at background priority 1     Server threads running at same priority as foreground (Default) 2     Server threads running one priority higher than foreground 15     Server threads running at real-time priority (Not Recommended)

NOTE: A value of 15 should never be used in production. If the server becomes busy, other important system process could become resource starved.  Quit Registry Editor and restart Windows NT.

WARNING: With the default Server ThreadPriority set to 1, changing the tasking option to "Foreground and Background Applications Equally Responsive" sets the server service priority to the same level as the foreground and background priorities. This could cause your server service to degrade in performance because it must now share time equally with other background processes.

