# 高效的 CPU 空闲功耗管理

CPU 空闲功耗管理（又称空闲功耗管理）可使 CPU 核保持在适当的休眠状态，以便在设备空闲时高效利用能源。

## CPU 休眠状态

一个 CPU 核支持多种休眠状态。每种休眠状态都有关联的进入和退出延迟以及不同的功耗级别。核休眠状态的选择取决于该核需要多久后再次执行任务。

一个 C 状态编号代表每种 CPU 休眠状态。每个 C 状态与两个关键参数相关联：

- 省电：当您选择更高的 C 状态时，CPU 的节能效果会提高，但这会导致唤醒延迟增加。
- 唤醒延迟：这是将 CPU 核从休眠状态转换为运行状态所需的时间。

例如，深度休眠状态 (C4) 具有更高的唤醒延迟和更低的功耗，如下图中所示。

![../../_images/latencypowersaving_1.png](data:image/png;base64,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)

**图：功耗和延迟之间的权衡**

可使用以下命令查看 CPU 休眠状态的延迟：

cat /sys/devices/system/cpu/cpu<X>/cpuidle/state<Y>/latency
    Copy to clipboard

Note

其中，`<X>` 表示核 ID，范围从 0 至 7，`<Y>` 是 Linux 电源状态的索引（0、1、2）。下表定义了 Linux 功耗状态。

您可以研究和配置休眠状态来调试应用程序，以实现功耗和性能的平衡。

下表列出了支持的 CPU 休眠状态及其关联的 C 状态编号：

Note

默认情况下，CPU 休眠状态处于启用状态。

表：支持的核电源状态

| CPU 休眠状态 | 说明 | Linux 电源状态 |
| --- | --- | --- |
| C1 | <ul class="simple"><br><li><p>CPU 核时钟域关闭</p></li><br><li><p>电源域 <code class="docutils literal notranslate"><span class="pre">VDD_APC0/</span> <span class="pre">VDD_APC1</span></code> 开启</p></li><br><li><p>通用中断控制器 (GIC) 时钟开启</p></li><br></ul> | State0 (S0) |
| C3 | <ul class="simple"><br><li><p>CPU 核时钟域关闭</p></li><br><li><p>核电源关闭，L1 和 L2 缓存刷新</p></li><br><li><p>电源域 <code class="docutils literal notranslate"><span class="pre">VDD_APC0/</span> <span class="pre">VDD_APC1</span></code> 开启</p></li><br></ul> | State1 (S1) |
| C4 | <ul class="simple"><br><li><p>小核群集的 C3 + PLL 关闭</p></li><br><li><p>大核和超大核群集的 C3 + PLL 电源域关闭</p></li><br></ul> | State2 (S2) |

## 启用/禁用 CPU 休眠状态

下表列出了如何配置 CPU 休眠状态：

Note

如果更改休眠状态的配置，则应检查电源对设备的影响。

| Linux 电源状态 | 启用/禁用 | 命令 |
| --- | --- | --- |
| S0 | 启用 | echo 0 > /sys/devices/system/cpu/cpu<X>/cpuidle/state0/disable<br>    Copy to clipboard |
| S0 | 禁用 | echo 1 > /sys/devices/system/cpu/cpu<X>/cpuidle/state0/disable<br>    Copy to clipboard |
| S1 | 启用 | echo 0 > /sys/devices/system/cpu/cpu<X>/cpuidle/state1/disable<br>    Copy to clipboard |
| S1 | 禁用 | echo 1 > /sys/devices/system/cpu/cpu<X>/cpuidle/state1/disable<br>    Copy to clipboard |
| S2 | 启用 | echo 0 > /sys/devices/system/cpu/cpu<X>/cpuidle/state2/disable<br>    Copy to clipboard |
| S2 | 禁用 | echo 1 > /sys/devices/system/cpu/cpu<X>/cpuidle/state2/disable<br>    Copy to clipboard |
|  |  |  |

Note

`<X>` 表示核 ID（从 0 到 7 不等）。

## 检查 CPU 空闲统计数据

要检查 CPU 核休眠状态的统计数据，可运行以下命令：

cat /sys/devices/system/cpu/cpu<X>/cpuidle/state<Y>/usage
    Copy to clipboard

这里，`<X>` 是核 ID，范围从 0 至 7，`<Y>` 是 Linux 电源状态的索引（0、1 和 2）。

以下是输出示例：

cd /sys/devices/system/cpu

grep -r “” cpu\*/cpuidle/\*/usage

cpu0/cpuidle/state0/usage:97681

cpu0/cpuidle/state1/usage:95

cpu1/cpuidle/state0/usage:180055

cpu1/cpuidle/state1/usage:59

Note

`usage` 计数表示 `cpu<X>` 进入 Linux 电源状态的次数。

Last Published: Oct 23, 2025

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