[This is preliminary documentation and subject to change]

Throttling Processes

If you run multiple Web sites on one computer, or if you have other applications running on the same computer as your Web server, you can limit how much processor time a Web site's out-of-process applications are permitted to utilize. This ensures that processor time is available to other Web sites or non-Web applications.

note Note If virtual directories within a throttled site are configured as in-process or pooled-process applications, the site may actually exceed the apparent processor use limit. In-process and pooled-process applications are not affected by processor throttling and are not included in process accounting statistics.

To decide whether you should use processor throttling

Use System Monitor to examine both the % Processor Time counter of the Processor object and, in the Web Service object, the specific instance counters for Maximum CGI Requests and Total CGI Requests.
Enable process acounting, so that the Job Object counter reports are included in IIS logs.
Examine the Dllhost object counters to determine the numbers of out-of-process WAM and ISAPI requests.

To throttle processor use by a Web site

In the IIS snap-in, select the Web site on which you want to restrict processor use.
Open the Web site's property sheets, and then click the Performance tab.
Select Enable process throttling and type the percentage of the CPU time that you want this site to be limited to.
Select Enforce limits if you want to enable the Level 2 and Level 3 consequences of processor time overrun.

Related Topics

For information on enabling process accounting, see About Logging Site Activity.
For information on application-specific performance issues and settings, see Configuring Applications.
For a list of counters provided by IIS, see Counters Reference.
For a list of all timeout values that can be set by IIS, see Timeouts Reference.