如何禁用动态频率缩放？ [英] How to Disable Dynamic Frequency Scaling?

问题描述

我想做一些微基准测试，并尽量做到正确。不幸的是，动态频率缩放使得基准测试非常不可靠。

有没有一种方法可以通过编程方式（C ++，Windows）如果，这可以在程序中禁用？

Ive试图在实际的基准测试之前使用一个使用100％CPU的热身阶段，但这个

更新：即使我在BIOS中禁用SpeedStep，cpu-z也显示频率在1995 and 2826 GHz

解决方案

一般来说，您需要执行以下步骤：

• 调用 CallNtPowerInformation（）并传递 SystemPowerCapabilities 到 InformationLevel 参数，将 lpInputBuffer 和 nInputBufferSize 设置为 NULL ，然后将 lpOutputBuffer < href =http://msdn.microsoft.com/en-us/library/aa373215(v=VS.85).aspx> SYSTEM_POWER_CAPABILITIES 结构，并将 nOutputBufferSize 设置为尺寸的结构。在第一次调用之后，包含当前系统电源功能的 SYSTEM_POWER_CAPABILITIES 结构。要检查系统是否支持处理器限制，请读取 ProcessorThrottle 的值。




• 还有我们感兴趣的其他两个成员，他们是：ProcessorMinThrottle 它们表示支持的系统处理器调节的最小和最大级别，以百分比表示。




• 要禁用CPU限制，请单击确定。如果两个成员都已经值100％，则表示CPU限制目前已停用，因此您无需重新配置。您需要将 ProcessorMinThrottle 和 ProcessorMaxThrottle 设置为 100％。为此，请再次调用 CallNtPowerInformation（）并将 SystemPowerCapabilities 传递到 InformationLevel 参数;但现在将 lpInputBuffer 设置为SYSTEM_POWER_CAPABILITIES结构，其中两个成员已设置为 100％。

在非程序化方式下，您还可以获取/设置Windows 使用Windows内置命令行工具，即 PowerCfg 。

进一步阅读

• 电源管理


• 电源管理功能

I would like to do some microbenchmarks, and try to do them right. Unfortunately dynamic frequency scaling makes benchmarking highly unreliable.

Is there a way to programmatically (C++, Windows) find out if dynamic frequency scaling is enabled? If, can this be disabled in a program?

Ive tried to just use a warmup phase that uses 100% CPU for a second before the actual benchmark takes place, but this turned out to be not reliable either.

UPDATE: Even when I disable SpeedStep in the BIOS, cpu-z shows that the frequency changes between 1995 and 2826 GHz

解决方案

In general, you need to do the following steps:

• Call CallNtPowerInformation() and pass SystemPowerCapabilities to InformationLevel parameter, set lpInputBuffer and nInputBufferSize to NULL, then set lpOutputBuffer to SYSTEM_POWER_CAPABILITIES structure, and set nOutputBufferSize to the size of the structure. After this first call, SYSTEM_POWER_CAPABILITIES structure containing the current system power capabilities. To check whether the system supports processor throttling, read the value of ProcessorThrottle.

• There are other two members we are interested in, they are, ProcessorMinThrottle and ProcessorMaxThrottle; they represents the minimum and maximum level of system processor throttling supported, expressed as a percentage. If both members has already values 100%, this means CPU throttling is currently disabled, so you don't need to reconfigure it.

• To disable CPU throttling, you need to set ProcessorMinThrottle and ProcessorMaxThrottle to 100%. To do this, call CallNtPowerInformation() again and pass SystemPowerCapabilities to InformationLevel parameter; but now, set lpInputBuffer to the SYSTEM_POWER_CAPABILITIES structure in which the two members has been set to 100%. I'm sure you know what to do next.

In non-programmatic way, you can also get/set Windows Power Options using the Windows built-in command-line tools, that is, PowerCfg.

Further Reading

• Power Management
• Power Management Functions

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