In some cases you may experience degraded overall performance on a Windows Server 2008 R2 or later machine when running with the default (Balanced) power plan. The issue may occur irrespective of platform and may be exhibited on both native and virtual environments. The degraded performance may increase the average response time for some tasks and cause performance issues with CPU-intensive applications.
Please note that you may not notice performance issues while performing simple operations. However, applications or scripts that intensively use resources (primarily processor and memory) may exhibit the problem. See More Information section for details.
This issue may occur if the Power Options settings are set to Balanced. By default, Windows Server 2008 R2 or later sets the Balanced (recommended) power plan, which enables energy conservation by scaling the processor performance based on current CPU utilization.
Option 1: Recommended
This issue is tied to interaction between the processors and the operating system not adjusting P-States and turning off Core Parking as needed. To address this it requires both hardware and operating system updates.
- Update System BIOS to a current revision. Reference the hardware manufacturer for model specific recommendations.
- Apply the appropriate hotfix for your operating system:
- For Windows Server 2008 R2 and Windows Server 2008 R2 Service Pack 1 - Apply the hotfix as per http://support.microsoft.com/?id=2534356.
- For Windows Server 2008 reference Option 2.
To work around the performance degradation issue, you can switch to the High Performance power plan. However, this will disable dynamic performance scaling on the platform. Depending on the environment, if the platform is always under a heavy load, then this is a viable solution. In most cases, however, the workload varies throughout the day and thus it is recommended to leave the power plan set to Balanced and evaluate the proper settings within the Balanced power plan for processor power management as described in the Processor Power Management in Windows 7 and Windows Server 2008 R2 paper located here:
Important: Today’s modern processors enable scaling of performance and power based on the current activity on the system. The different performance states are dynamically managed by Windows in conjunction with hardware and platform firmware to respond to varying workload requirements. The 3 default power plans exposed by Windows provide varying tradeoffs of performance vs. power consumption. For example, if the High Performance power plan is selected, Windows places the system in the highest performance state and disables the dynamic scaling of performance in response to varying workload levels. Therefore, special care should be taken before setting the power plan to High Performance as this can increase power consumption unnecessarily when the system is underutilized.
If the choice is made to change the default power plan, Windows Server 2008 R2 or later provides three power plans to maximize performance and conserve energy: Balanced (recommended), High Performance and Power Saver.
To change a power plan:
1. Click on Start and then Control Panel.
2. From the list of displayed item under Control Panel click on Power Options, which takes you to Select a power plan page. If you do not see Power Options, type the word 'power' in the Search Control Panel box and then select Choose a power plan.
3. By default, the option to change power plans is disabled. To enable this, click the Change settings that are currently unavailable link.
4. Choose the High Performance option
5. Close the Power Option window.
Processors change between performance states (“P-states”) very quickly to match supply to demand, delivering performance where necessary and saving power when possible. If your server has specific high-performance or minimum-power-consumption requirements, you might consider configuring the Minimum or Maximum Processor Performance State parameter. The values for both the Minimum and Maximum Processor Performance State parameters are expressed as a percentage of maximum processor frequency, with a value in the range 0 – 100. If your server requires low latency, invariant frequency, or high performance, you might not want the processors switching to lower-performance states.
For general guidelines on performance, consult the Performance Tuning Guidelines for Windows Server 2008 R2 paper located here:
During several tests, the issue discussed above was observed on:
- Four HP Proliant DL585G2 physical machines in customer's environment
- A Dell Optiplex 755 in-house
- A Hyper-V Virtual machine
The degraded performance, as referred here, is relative to that on a Windows Server 2003 (x64) SP2. Resource intensive applications like SQL which is querying large database files by means of direct query or stored procedure, took comparatively more time on Windows Server 2008 R2 than Windows Server 2003 (x64) SP2. A simple script that writes 500K lines to a log file under test, took 30 minutes on a Windows Server 2003 (x64) SP2 and 50 plus minutes on Windows Server 2008 R2.
One of the several changes in Windows Server 2008 R2 is in power consumption. You can configure your machine which runs Windows Server 2008 R2 to run in a Power Saver mode (which actually is a preset of power management) to conserve maximum energy. This enables advanced feature like Core Parking (in multicore hardware). Refer to http://www.microsoft.com/windowsserver2008/en/us/r2-management.aspx.
High Performance option uses more energy. But you can customize a power plan by choosing Change plan settings followed by Change advance power settings and then configure the computer to manage power.
Important Note: Before you customize power management options for a Power Plan, make sure you know what a power setting will change on your system.
Additionally, installing Support Pack for Windows Server 2008 R2 on the machine may also help improving the efficiency. Support packs are hardware vendor specific.
Steps to reproduce.
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Id. de artículo: 2207548 - Última revisión: 2 feb. 2017 - Revisión: 2