FIX: An application may experience latency when it requires long running or many communications between the Aspnet_wp.exe and the Inetinfo.exe processes (835680)


The information in this article applies to:

  • Microsoft .NET Framework 1.1
  • Microsoft Visual Studio .NET (2003), Enterprise Architect Edition
  • Microsoft Visual Studio .NET (2003), Enterprise Developer Edition
  • Microsoft Visual Studio .NET (2003), Professional Edition
  • Microsoft ASP.NET (included with the .NET Framework 1.1)

SYMPTOMS

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.

CAUSE

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.

RESOLUTION

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:

http://support.microsoft.com/contactus/?ws=support

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

WORKAROUND

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.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article.
Modification Type:MinorLast Reviewed:10/25/2005
Keywords:kbHotfixServer kbQFE kbBug kbfix kbQFE kbNetFrame110preSP1fix KbSECTools kbcritsit KB835680 kbAudDeveloper
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