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When a managed Microsoft .NET Framework application uses the System.Threading.Timer class in the Microsoft .NET Framework 1.1 Service Pack 1 (SP1), the timer event may not be signaled. Typically, this problem occurs if the computer that is running the application is under a heavy load or if many timer objects are running.
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.
To download this hotfix from the MSDN Code Gallery, visit the following Microsoft Web site:
Note The MSDN Code Gallery displays the languages for which the hotfix is available. If you do not see your language listed, it is because the Code Gallery resource page is not available for that language.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:
You do not have to restart the computer after you apply this software update.
Software update replacement information
This software update does not replace any other software updates.
The English version of this software update has the file attributes (or later file attributes) 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 ---------------------------------------------------------- 09-Jun-2005 05:46 1.1.4322.2331 2,138,112 Mscorlib.dll 09-Jun-2005 05:48 10,908 Mscorlib.ldo 09-Jun-2005 05:56 1.1.4322.2331 2,519,040 Mscorsvr.dll 09-Jun-2005 05:57 1.1.4322.2331 2,506,752 Mscorwks.dll
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The Timer classes are implemented as a linked list of timer objects. When the first System.Threading.Timer object is created, the thread pool manager starts a thread to process the linked list. Every timer object is added to the linked list. The thread that process the linked list cycles through the linked list and determines when the timer event is expected to be signaled against the current clock count.
If the timer object has expired, the thread asynchronously queues a callback function before the thread updates the time that the timer event is expected to be signaled. After the thread has processed all timer objects in the linked list, the thread updates the time that the linked list was last processed. Then, the thread calculates the shortest time that the thread should sleep before the thread reprocesses the linked list for the next elapsed timer object.
Sometimes, when the system is under stress or when the linked list includes many timer objects, the processing thread may be pre-empted by a higher priority thread before the whole linked list has been processed. When this behavior occurs, the time that a timer event is next expected to be signaled is calculated to be earlier than the timestamp when the linked list was last processed. Therefore, the time that the timer event is expected to be signaled is in the past and never expires.
Because the time that the timer event is expected to be signaled has already passed, the thread may calculate a negative period to wait before the timer event must be signaled. When the thread has a negative period to wait, the thread enters a sleep state for a long time.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates