3 种软件方法获取 Android 设备的功耗

发表于 2025-02-26

硬件方法获取功耗虽然准确，但需要功耗版/power monitor，成本较高，且不方便。Android 系统中也有软件测功耗的方法，下面分别介绍 BatteryManager 类， adb 和 Perfetto 方法。

BatteryManager 类

适用于应用上层，在 SDK 21 及以上可用。

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BatteryManager batteryManager = (BatteryManager) getSystemService(BATTERY_SERVICE);
int currentNow = batteryManager.getIntProperty(BatteryManager.BATTERY_PROPERTY_CURRENT_NOW); // 当前电流，单位mA
}

Adb 方法

shell:/ $ find -name current_now 2>/dev/null # adb shell 中输入
./sys/devices/platform/soc/a90000.i2c/i2c-4/4-0036/power_supply/maxfg/current_now
shell:/ $ cat ./sys/devices/platform/soc/a90000.i2c/i2c-4/4-0036/power_supply/maxfg/current_now
312 # 当前电流，整数表示充电，单位为mA

Perfetto 测器件功耗

瞬时功耗波动很大，以上两个接口获取的数据很可能并不准确。使用 Perfetto 可以监控并获取一段时间的功耗。

Wattson 测 CPU 每个核心的功耗

CPU 性能功耗相关数据获取

Capacity:

1	cat /sys/devices/system/cpu/cpu*/cpu_capacity

获得最高频的capacity，其他频率的可以直接折算。

Power:

芯片的dtsi中会有，可以直接在内核中dts文件夹进行寻找

https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/

如果没有找到，可以重新编译内核，在energy_model初始化时加一句printk打印出来。

diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index c2c858c6d56d..db95d74f00d7 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -149,6 +149,7 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
 
                table[i].power = power;
                table[i].frequency = prev_freq = freq;
+               dev_info(dev, "#%d: freq:%lu power:%lu\n", i, freq, power);
        }
 
        /* Compute the cost of each performance state. */

就可以打印出这样的信息：

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cpu cpu0: #0: freq:300000 power:10
cpu cpu0: #1: freq:441600 power:15
......

capacity/power，就可以得到能效比(energy efficiency ratio,EER)

如骁龙 8+gen1 sm8475 的EER表：

使用Wattons插件

有了频点对应的power表后，可以使用perfetto的wattson插件预估功耗，这个工具会基于每个核频点和运行时间计算功耗。使用前，需要把energy_model中的 power 数据导入到perfetto的 sql 中。

先将perfetto源码clone下来

1	git clone https://android.googlesource.com/platform/external/perfetto/

然后将刚刚的power数据加到src/trace_processor/perfetto_sql/stdlib/wattson/curves/device.sql 中的_device_curves_1d表中，由于我们只知道运行时功耗，将 static, idle0, idle1 功耗都填0，active功耗填em的power。

在src/trace_processor/perfetto_sql/stdlib/wattson/device_info.sql 中

_wattson_device_map表中将CPU和手机的型号对应，手机型号应该在 adb shell 时会打印在 shell 输入的左边，如k60是mondrian。
在 _device_cpu_deep_idle_offsets 表写每个核心的idle时间，每个核心直接写0
在_cpu_to_policy_map 表写每个 cpu 核对应的调频policy
在 _device_min_volt_vote 表中填小核最低频点

如 sm8475 的数据：

diff --git a/src/trace_processor/perfetto_sql/stdlib/wattson/curves/device.sql b/src/trace_processor/perfetto_sql/stdlib/wattson/curves/device.sql
index be56de6d32..c8a0ef5e21 100644
--- a/src/trace_processor/perfetto_sql/stdlib/wattson/curves/device.sql
+++ b/src/trace_processor/perfetto_sql/stdlib/wattson/curves/device.sql
@@ -95,7 +95,58 @@ WITH data(device, policy, freq_khz, static, active, idle0, idle1) AS (
   ("neo", 0, 1113600, 5.65, 32.33, 0.99, 0),
   ("neo", 0, 1497600, 7.19, 45.89, 1.51, 0),
   ("neo", 0, 1804800, 11.7, 99.98, 2.22, 0),
-  ("neo", 0, 1996800, 12.5, 101.04, 2.62, 0)
+  ("neo", 0, 1996800, 12.5, 101.04, 2.62, 0),
+  ("s8pg1", 0, 300000, 0, 10, 0, 0),
+  ("s8pg1", 0, 441600, 0, 15, 0, 0),
+  ("s8pg1", 0, 556800, 0, 19, 0, 0),
+  ("s8pg1", 0, 691200, 0, 26, 0, 0),
+  ("s8pg1", 0, 806400, 0, 31, 0, 0),
+  ("s8pg1", 0, 940800, 0, 38, 0, 0),
+  ("s8pg1", 0, 1056000, 0, 45, 0, 0),
+  ("s8pg1", 0, 1132800, 0, 51, 0, 0),
+  ("s8pg1", 0, 1228800, 0, 58, 0, 0),
+  ("s8pg1", 0, 1324800, 0, 66, 0, 0),
+  ("s8pg1", 0, 1440000, 0, 78, 0, 0),
+  ("s8pg1", 0, 1555200, 0, 90, 0, 0),
+  ("s8pg1", 0, 1670400, 0, 103, 0, 0),
+  ("s8pg1", 0, 1804800, 0, 120, 0, 0),
+  ("s8pg1", 4, 633600, 0, 58, 0, 0),
+  ("s8pg1", 4, 768000, 0, 75, 0, 0),
+  ("s8pg1", 4, 883200, 0, 90, 0, 0),
+  ("s8pg1", 4, 998400, 0, 107, 0, 0),
+  ("s8pg1", 4, 1113600, 0, 124, 0, 0),
+  ("s8pg1", 4, 1209600, 0, 140, 0, 0),
+  ("s8pg1", 4, 1324800, 0, 164, 0, 0),
+  ("s8pg1", 4, 1440000, 0, 189, 0, 0),
+  ("s8pg1", 4, 1555200, 0, 216, 0, 0),
+  ("s8pg1", 4, 1651200, 0, 242, 0, 0),
+  ("s8pg1", 4, 1766400, 0, 273, 0, 0),
+  ("s8pg1", 4, 1881600, 0, 306, 0, 0),
+  ("s8pg1", 4, 1996800, 0, 338, 0, 0),
+  ("s8pg1", 4, 2112000, 0, 379, 0, 0),
+  ("s8pg1", 4, 2227200, 0, 415, 0, 0),
+  ("s8pg1", 4, 2342400, 0, 461, 0, 0),
+  ("s8pg1", 4, 2496000, 0, 514, 0, 0),
+  ("s8pg1", 7, 787200, 0, 138, 0, 0),
+  ("s8pg1", 7, 921600, 0, 173, 0, 0),
+  ("s8pg1", 7, 1036800, 0, 202, 0, 0),
+  ("s8pg1", 7, 1171200, 0, 244, 0, 0),
+  ("s8pg1", 7, 1286400, 0, 274, 0, 0),
+  ("s8pg1", 7, 1401600, 0, 314, 0, 0),
+  ("s8pg1", 7, 1536000, 0, 361, 0, 0),
+  ("s8pg1", 7, 1651200, 0, 411, 0, 0),
+  ("s8pg1", 7, 1766400, 0, 465, 0, 0),
+  ("s8pg1", 7, 1881600, 0, 524, 0, 0),
+  ("s8pg1", 7, 1996800, 0, 593, 0, 0),
+  ("s8pg1", 7, 2131200, 0, 666, 0, 0),
+  ("s8pg1", 7, 2246400, 0, 731, 0, 0),
+  ("s8pg1", 7, 2361600, 0, 808, 0, 0),
+  ("s8pg1", 7, 2476800, 0, 880, 0, 0),
+  ("s8pg1", 7, 2592000, 0, 975, 0, 0),
+  ("s8pg1", 7, 2707200, 0, 1057, 0, 0),
+  ("s8pg1", 7, 2822400, 0, 1153, 0, 0),
+  ("s8pg1", 7, 2918400, 0, 1257, 0, 0),
+  ("s8pg1", 7, 2995200, 0, 1347, 0, 0)
 )
 select * from data;
 
diff --git a/src/trace_processor/perfetto_sql/stdlib/wattson/device_infos.sql b/src/trace_processor/perfetto_sql/stdlib/wattson/device_infos.sql
index e5a37d1431..c2fb9c6b7b 100644
--- a/src/trace_processor/perfetto_sql/stdlib/wattson/device_infos.sql
+++ b/src/trace_processor/perfetto_sql/stdlib/wattson/device_infos.sql
@@ -43,7 +43,15 @@ WITH data(device, cpu, offset_ns) AS (
   ("neo", 0, 100000),
   ("neo", 1, 100000),
   ("neo", 2, 100000),
-  ("neo", 3, 100000)
+  ("neo", 3, 100000),
+  ("s8pg1", 0, 0),
+  ("s8pg1", 1, 0),
+  ("s8pg1", 2, 0),
+  ("s8pg1", 3, 0),
+  ("s8pg1", 4, 0),
+  ("s8pg1", 5, 0),
+  ("s8pg1", 6, 0),
+  ("s8pg1", 7, 0)
 )
 select * from data;
 
@@ -55,7 +63,8 @@ WITH data(device, wattson_device) AS (
   ("raven", "Tensor"),
   ("bluejay", "Tensor"),
   ("eos", "monaco"),
-  ("aurora", "monaco")
+  ("aurora", "monaco"),
+  ("mondrian", "s8pg1")
 )
 select * from data;
 
@@ -110,7 +119,15 @@ WITH data(device, cpu, policy) AS (
   ("neo", 0, 0),
   ("neo", 1, 0),
   ("neo", 2, 0),
-  ("neo", 3, 0)
+  ("neo", 3, 0),
+  ("s8pg1", 0, 0),
+  ("s8pg1", 1, 0),
+  ("s8pg1", 2, 0),
+  ("s8pg1", 3, 0),
+  ("s8pg1", 4, 4),
+  ("s8pg1", 5, 4),
+  ("s8pg1", 6, 4),
+  ("s8pg1", 7, 7)
 )
 select * from data;
 
@@ -132,7 +149,8 @@ WITH data(device, policy, freq) AS (
   ("monaco", 0, 614400),
   ("Tensor", 4, 400000),
   ("Tensor G4", 0, 700000),
-  ("neo", 0, 691200)
+  ("neo", 0, 691200),
+  ("s8pg1", 0, 614400)
 )
 select * from data;

保存后编译perfetto：

# Install build dependencies
tools/install-build-deps --ui

# This will automatically build the UI. There is no need to manually run# ui/build before running ui/run-dev-server.
ui/run-dev-server

服务器会在 localhost:10000 中执行，按照教程抓一个trace，应该就能看到功耗了。

注意事项：因为energy_model中power单位不确定，两个不同设备的power不可直接用于比较。

Battery counters 测电池消耗的电量

需要设备上存在电源管理硬件。大多数 Google Pixel 智能手机都支持

此功能。注意需要断开USB测试。

Sample config:

data_sources: {
    config {
        name: "android.power"
        android_power_config {
            battery_poll_ms: 250
            battery_counters: BATTERY_COUNTER_CAPACITY_PERCENT
            battery_counters: BATTERY_COUNTER_CHARGE
            battery_counters: BATTERY_COUNTER_CURRENT
            battery_counters: BATTERY_COUNTER_VOLTAGE
        }
    }
}

perfetto的batt.charge_uah是当前电量，前后数值一减就是消耗的电量。

ODPM 测元器件的功耗

pixel 6 以上（含6）的pixel手机支持On-Device Power Rails Monitor (ODPM)，在硬件层面做了更细粒度电源监控的支持，可以测量不同元器件的功耗。在平台级别，此数据是通过轮询 Android IPowerStats HAL 获得的。

Sample config:

data_sources: {
    config {
        name: "android.power"
        android_power_config {
            battery_poll_ms: 250
            collect_power_rails: true
            # Note: it is possible to specify both rails and battery counters
            # in this section.
        }
    }
}

下面介绍如何使用ODPM对pixel 8功耗进行测量。

config.pbtx：

buffers: {
    size_kb: 63488
    fill_policy: DISCARD
}
buffers: {
    size_kb: 2048
    fill_policy: DISCARD
}
data_sources: {
    config {
        name: "android.power"
        android_power_config {
            battery_poll_ms: 1000
            collect_power_rails: true
        }
    }
}

duration_ms: 10000