When an application requires long running communication or many communications between the Aspnet_wp.exe and the Inetinfo.exe processes, you may experience periodic latency in the application and queuing that may last up to 20 minutes. Also, static content may not render.
Named Pipes are used to call Microsoft Internet Information Services (IIS) APIs from the Aspnet_wp.exe process to communicate with the Inetinfo.exe process. For example, you may use this communication to set
permissions on application folders or to access session data. If all Named Pipes are in use, other threads in the Aspnet_wp.exe process may be prevented from executing. This behavior causes the problem that is described in the "Symptoms" section of this article.
To resolve this problem, install this hotfix. After you install the hotfix, add
SyncPipesPerCPU
as a DWORD value in the registry under the
HKLM\Software\Microsoft\ASP.NET
registry key:
HKLM\Software\Microsoft\ASP.NET\SyncPipesPerCPU
.
Set the
Value Data property for the
SyncPipesPerCPU value to the number of Named Pipes for each CPU that you want.
Note You must do significant performance testing if you use this hotfix. The
SyncPipesPerCPU value is used to determine the
optimal number of synchronous pipes for each CPU. If the value of
SyncPipesPerCPU is too low, performance may decrease. If the value of
SyncPipesPerCPU is too high, too many resources may be used. By default, four Named Pipes are used for each CPU. For most Web applications, four Named Pipes are sufficient.
Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft .NET Framework 1.1 Service Pack 1 that contains this hotfix.
To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
File information
The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the
Time Zone tab in the Date and Time tool in Control Panel.
Date Time Version Size File name
---------------------------------------------------------------------------------------------
05-Feb-2004 04:00 1.1.4322.997 258,048 Aspnet_isapi.dll
05-Feb-2004 04:00 1.1.4322.997 20,480 Aspnet_regiis.exe
05-Feb-2004 04:00 1.1.4322.997 32,768 Aspnet_state.exe
05-Feb-2004 04:00 1.1.4322.997 32,768 Aspnet_wp.exe
16-May-2003 00:49 33,522 Installpersistsqlstate.sql
16-May-2003 00:49 34,150 Installsqlstate.sql
05-Feb-2004 03:50 1.1.4322.997 94,208 Perfcounter.dll
05-Feb-2004 03:55 8,571 Smartnav.js
07-Feb-2004 00:05 1.1.4322.997 1,220,608 System.dll
07-Feb-2004 00:05 1.1.4322.997 241,664 System.messaging.dll
07-Feb-2004 00:05 1.1.4322.997 323,584 System.runtime.remoting.dll
07-Feb-2004 00:05 1.1.4322.997 131,072 System.runtime.serialization.formatters.soap.dll
07-Feb-2004 00:05 1.1.4322.997 1,257,472 System.web.dll
07-Feb-2004 00:05 1.1.4322.997 819,200 System.web.mobile.dll
07-Feb-2004 00:05 1.1.4322.997 569,344 System.web.services.dll
07-Feb-2004 00:05 1.1.4322.997 1,339,392 System.xml.dll
05-Feb-2004 03:55 14,482 Webuivalidation.js
To work around this problem, you can upgrade to IIS 6.0. In IIS 6.0, you can have separate processes so all Named Pipe communication will not occur in the same process and cause latency.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article.