调用SetProcessInformation参数无效，如何为进程设置Eco QOS模式？

错误码87是典型的参数无效问题，你的代码存在三个关键错误，逐一修正即可解决：

1. 错误的ProcessPowerThrottling枚举值 #

你将ProcessPowerThrottling设为4，但根据Windows API定义，PROCESS_INFORMATION_CLASS枚举中的ProcessPowerThrottling成员数值应为92（0x5C）。这个错误直接导致API无法识别你要设置的信息类别，是引发错误87的核心原因之一。

2. PROCESS_POWER_THROTTLING_STATE的ControlMask未正确设置 #

根据文档，ControlMask字段需要指定你想要修改的节流状态位，不能设为0。启用Eco QOS时，ControlMask和StateMask都要设置为PROCESS_POWER_THROTTLING_EXECUTION_SPEED；禁用时，ControlMask保持该值，StateMask设为0。

3. GetLastError调用方式不可靠 #

直接调用windll.kernel32.GetLastError可能被其他ctypes操作覆盖错误码，应使用ctypes.get_last_error()来获取准确的错误信息。

修正后的完整代码 #

import ctypes
from ctypes import windll, wintypes
from typing import Any

class PROCESS_POWER_THROTTLING_STATE(ctypes.Structure):
    _fields_ = [
        ('Version',     wintypes.ULONG),
        ('ControlMask', wintypes.ULONG),
        ('StateMask',   wintypes.ULONG)
    ]

def setEcoQOS(pid: int, enable: bool):
    PROCESS_SET_INFORMATION = 0x0200
    PROCESS_POWER_THROTTLING_CURRENT_VERSION = 1
    PROCESS_POWER_THROTTLING_EXECUTION_SPEED = 0x1
    # 修正ProcessPowerThrottling的枚举值为正确的92（0x5C）
    ProcessPowerThrottling = 0x5C

    SetProcessInformation = windll.kernel32.SetProcessInformation
    SetProcessInformation.argtypes = (
        wintypes.HANDLE,
        wintypes.DWORD,
        wintypes.LPVOID,
        wintypes.DWORD,
    )
    SetProcessInformation.restype = wintypes.BOOL

    OpenProcess = windll.kernel32.OpenProcess
    OpenProcess.argtypes = (
        wintypes.DWORD,
        wintypes.BOOL,
        wintypes.DWORD,
    )
    OpenProcess.restype = wintypes.HANDLE

    CloseHandle = windll.kernel32.CloseHandle
    CloseHandle.argtypes = (wintypes.HANDLE,)
    CloseHandle.restype = wintypes.BOOL

    hwnd = OpenProcess(PROCESS_SET_INFORMATION, False, pid)
    if hwnd == 0:
        raise Exception(f'无法打开进程PID {pid}，错误码={ctypes.get_last_error()}')

    PowerThrottling = PROCESS_POWER_THROTTLING_STATE()
    PowerThrottling.Version = PROCESS_POWER_THROTTLING_CURRENT_VERSION
    PowerThrottling.ControlMask = PROCESS_POWER_THROTTLING_EXECUTION_SPEED
    if enable:
        PowerThrottling.StateMask = PROCESS_POWER_THROTTLING_EXECUTION_SPEED
    else:
        PowerThrottling.StateMask = 0

    ret = SetProcessInformation(hwnd, ProcessPowerThrottling, ctypes.byref(PowerThrottling), ctypes.sizeof(PowerThrottling))
    if not ret:
        raise Exception(f'无法设置进程信息，错误码={ctypes.get_last_error()}')

    ret = CloseHandle(hwnd)
    if not ret:
        raise Exception(f'无法关闭句柄，错误码={ctypes.get_last_error()}')


pid = 10688 # 替换为你的目标PID
setEcoQOS(pid, True)

为subprocess.Popen启动的进程设置Eco QOS #

如果要为subprocess.Popen启动的进程自动启用该模式，只需在创建进程后立即调用setEcoQOS，传入子进程的pid：

import subprocess

proc = subprocess.Popen(["your_executable.exe"])
setEcoQOS(proc.pid, True)

内容的提问来源于stack exchange，提问作者notsoeasy