Registry Entries for Thread Pool Queuing

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Applies To: Windows Server 2003, Windows Server 2003 with SP1

The following entries in the Windows registry determine the number of threads in the IIS thread pool. Tuning thread pools can produce dramatic improvement in IIS performance and scalability.

MaxPoolThreads

Specifies the maximum number of pool threads per processor. This is not an absolute limit; that is, IIS can increase the number of threads if the current load would benefit from having more threads available. Pool threads monitor the network for requests and process incoming requests. The value of MaxPoolThreads does not include threads that are consumed by ISAPI applications.

PoolThreadLimit

Specifies the maximum number of pool threads that can be created in the system. Pool threads monitor the network for requests and process incoming requests. PoolThreadLimit is an absolute limit that includes all core Web service threads. It is always greater than or equal to the value of MaxPoolThreads.

For more information about these registry entries, see the Global Registry Entries reference, and Optimizing IIS 6.0 Performance.