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CoCreateInstance Under Stress on Multiple Threads at the Same Time Causes Long Hangs or Returns Failure

Article ID: 187884 - View products that this article applies to.

This article was previously published under Q187884

SYMPTOMS

Calling CoCreateInstance on multiple threads at the same time causes the computer to not respond (hang) for long periods of time. No desktop activity can be performed during this time. PerfMon logs during the time the computer is not responding show no signs that the computer is stressed. The idle thread has more than 95 percent of the CPU time while the computer is not responding. This problem was originally identified when hosting ASP pages that issue CoCreateInstance requests. When under stress, the computer would cease responding. CoCreateInstance requests would fail with the E_OUTOFMEMORY error leading up to the time when the computer quits responding.

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CAUSE

The problem is caused by a shortage in the LPC resource pool. All threads that request LPC pool storage are in a wait (a two-minute timeout) for a free pool request to post that pool storage is available. Explorer.exe threads that need LPC pool storage will also wait. Since no free pool requests come through, all threads wait for two minutes, giving the appearance of a system hang. When the two minute timeout expires, the pool is expanded and all threads begin running again.

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RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

152734

(http://support.microsoft.com/kb/152734/EN-US/ )

How to Obtain the Latest Windows NT 4.0 Service Pack

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STATUS

Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

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