Performance Improvement for Redirector/Server Connections Involving Small File Operations

ID: Q236316

The information in this article applies to:

SYMPTOMS

Programs that perform numerous small file operations, such as locking and unlocking files or writing small records, may experience slow performance.


CAUSE

This problem occurs because the combination of "Nagling" (a TCP concept described in the Microsoft Knowledge Base and white papers) and TCP delayed acknowledgment can cause unnecessary network delay when numerous small file operations are outstanding between a client and server. More details on Nagling are available from:

ftp://ftp.microsoft.com/bussys/winnt/winnt-docs/papers/tcpipimp2.doc


RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp


The English version of this fix should have the following file attributes or later:

   Date      Time     Size      File name   Platform
   --------------------------------------------------
   06/28/99  01:10p   123,120   Netbt.sys   x86
   06/28/99  01:09p   224,144   Netbt.sys   Alpha

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:
Q154871 Determining If You Are Eligible for No-Charge Technical Support


STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0.


MORE INFORMATION

The Netbt.sys driver has been modified to disable nagling in the TCP stack for NetBT connections.

Additional query words: 


Keywords          : kbbug4.00 kbfix4.00 
Version           : winnt:4.0
Platform          : winnt 
Issue type        : kbbug

Last Reviewed: July 30, 1999