Console-mode Apps May Run Slowly on Multiprocessor Computers

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

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 work around this problem, use either of the following methods:

Specify the /NUMCPU=1 option in the Boot.ini file and then restart Windows NT. This effectively downgrades the system to a single processor computer, which does not normally experience this problem.

   -or-

This fix should have the following time stamp:

   10/13/97  05:01p               175,376 winsrv.dll  (Intel)
   10/13/97  04:59p               315,152 winsrv.dll  (Alpha)

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

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.