Windows EcoQoS / Efficency Mode Enabler CLI

eco.cs

// C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe /o /platform:x64 eco.cs && C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe install eco.exe
// Known issue: not work and no error for UWP apps.

using System;
using System.Diagnostics;
using System.Runtime;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.ComponentModel;

static class Eco
{
    [DllImport("Kernel32", SetLastError = true)]
    static extern bool SetProcessInformation(IntPtr hProcess, int PROCESS_INFORMATION_CLASS, ref PROCESS_POWER_THROTTLING_STATE pi, int ProcessInformationSize);

    struct PROCESS_POWER_THROTTLING_STATE
    {
        public uint Version;
        public uint ControlMask;
        public uint StateMask;
    }

    const int ProcessPowerThrottling = 4;
    const int PROCESS_POWER_THROTTLING_CURRENT_VERSION = 1;
    const int PROCESS_POWER_THROTTLING_EXECUTION_SPEED = 1;
    static readonly int STATE_SIZE = Marshal.SizeOf<PROCESS_POWER_THROTTLING_STATE>();
    static PROCESS_POWER_THROTTLING_STATE STATE = new PROCESS_POWER_THROTTLING_STATE
    {
        Version = PROCESS_POWER_THROTTLING_CURRENT_VERSION,
        ControlMask = PROCESS_POWER_THROTTLING_EXECUTION_SPEED,
        StateMask = PROCESS_POWER_THROTTLING_EXECUTION_SPEED
    };

    public static string Set(IntPtr hProcess)
    {
        if (!SetProcessInformation(hProcess, ProcessPowerThrottling, ref STATE, STATE_SIZE))
            return new Win32Exception(Marshal.GetLastWin32Error()).Message;
        return null;
    }
}

class Program
{
    static int Main(string[] args)
    {
        GCSettings.LatencyMode = GCLatencyMode.LowLatency;

        if (args.Length == 0)
        {
            Console.WriteLine("Usage: eco notepad ...");
            return 0;
        }

        var targetPs = new HashSet<string>(args);

        int cnt = 0;

        foreach(var p in Process.GetProcesses())
        {
            if (targetPs.Contains(p.ProcessName.ToLowerInvariant()))
            {
                string ret = Eco.Set(p.Handle);
                if (ret != null)
                    Console.Error.WriteLine("Failed to access {0}: {1}", p.ProcessName, ret);
                else
                    cnt++;
            }
        }

        if (cnt != args.Length)
        {
            Console.Error.WriteLine("{0} succeed.", cnt);
            return 1;
        }
        else
            return 0;
    }
}