Console-mode Applications May Run Slowly on Multi-Processor Computers (176211)

SYMPTOMS

A series of MS-DOS-based console applications may take a long time (perhaps several minutes) to complete on a multiprocessor computer. The console windows may remain blank and appear to stop responding (hang). All the applications do eventually finish, but this may take an unusual amount of time.

The same series of applications will finish in a few seconds on a single processor computer.

CAUSE

A console handle table lock is being held too long during the freeing of a console. Processing for other console-related activities is delayed while the lock is held.

The problem is not usually seen on single processor computers as a context switch to another console process is unlikely during console cleanup. On a multiprocessor computer, however, multiple console-mode processes may be executing simultaneously, which greatly increases the chance of encountering this problem.

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 How to Obtain the Latest Windows NT 4.0 Service Pack

This fix modifies console handling so that the handle table lock is released during noncritical sections of console cleanup. This allows other simultaneously executing console processes to continue and finish in a reasonable time frame.

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.

MORE INFORMATION

All MS-DOS console-mode applications are affected by this problem on multiprocessor computers under Windows NT 4.0. Windows applications are not affected.

This problem has been seen when attempting to start multiple PERL scripts as CGI applications run in console-mode on multiprocessor intranet web servers.