CPU usage is abnormally high when SAP processes use the new SAP flat memory model on a Windows Server 2003-based computer

Consider the following scenario. On a Microsoft Windows Server 2003-based computer, you are running SAP. Additionally, the SAP processes use the new SAP flat memory model. In this scenario, the system experiences abnormally high CPU usage. For example, CPU usage may be 50 percent or more. This high CPU usage adversely affects computer performance.

Note This problem does not occur when SAP processes use the old hierarchical SAP memory model.

This problem occurs because the working set hash table is expanded in increments. However, these increments are too small. Therefore, the hash table expansion process is very resource-intensive.

Service pack information

To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

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.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

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: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix 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.

Windows Server 2003, Itanium-based versions

Windows Server 2003, x64-based versions

Windows Server 2003, x86-based versions

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Server 2003 Service Pack 2.

The latest deployed release of SAP introduces a flat memory model for 64-bit operating systems. In the earlier SAP model, SAP processes use a memory-mapped file to steadily map and unmap 1-megabyte (MB) segments. In the flat memory model, the memory-mapped file is replaced by shared memory. The flat memory model does not use the Map and Unmap calls that use serialized code in Windows. The flat memory model benefits high-end servers that use multicore processors. A throughput improvement of up to 10 percent has been measured when the flat memory model is used. For more information, click the following article number to view the article in the Microsoft Knowledge Base: