c# - 如何在 C# 中限制 CPU 使用率

Question

我正在制作一个 C# 程序。我的程序正在调用另一个程序。问题是我正在调用的程序正在消耗 100% 的 CPU。因此，我想将其限制为 CPU 使用率的恒定百分比。是否可以？如何？

Answer 1

您是否有任何理由要将其限制为特定的 CPU 使用百分比？以较低的优先级运行它怎么样，这样它在没有其他需要时仍然使用 100% 的 CPU，但在有更重要的进程运行时被置于后台？

Answer 2

这在搜索引擎中仍然是一个比较高的结果，所以我将针对这个老问题添加一个答案：

是的！

在 Windows 8+ 中，您可以使用 Jobs 限制进程 CPU 消耗：

使用JobObjectCpuRateControlInformation调用SetInformationJobObject并设置。JOB_OBJECT_CPU_RATE_CONTROL_ENABLE | JOB_OBJECT_CPU_RATE_CONTROL_HARD_CAP

Job API 是原生的，所以你必须 p/invoke 到它：

    public static class Win32
    {
        public enum JobObjectInfoType
        {
            AssociateCompletionPortInformation = 7,
            BasicLimitInformation = 2,
            BasicUIRestrictions = 4,
            EndOfJobTimeInformation = 6,
            ExtendedLimitInformation = 9,
            SecurityLimitInformation = 5,
            GroupInformation = 11,
            JobObjectCpuRateControlInformation = 15
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct JOBOBJECT_BASIC_LIMIT_INFORMATION
        {
            public Int64 PerProcessUserTimeLimit;
            public Int64 PerJobUserTimeLimit;
            public JOBOBJECTLIMIT LimitFlags;
            public UIntPtr MinimumWorkingSetSize;
            public UIntPtr MaximumWorkingSetSize;
            public UInt32 ActiveProcessLimit;
            public Int64 Affinity;
            public UInt32 PriorityClass;
            public UInt32 SchedulingClass;
        }

        [Flags]
        public enum JOBOBJECTLIMIT : uint
        {
            JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE = 0x2000,
            JOB_OBJECT_LIMIT_JOB_MEMORY = 0x00000200,
            JOB_OBJECT_LIMIT_PROCESS_MEMORY = 0x00000100,
            JOB_OBJECT_LIMIT_WORKINGSET = 0x00000001
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct IO_COUNTERS
        {
            public UInt64 ReadOperationCount;
            public UInt64 WriteOperationCount;
            public UInt64 OtherOperationCount;
            public UInt64 ReadTransferCount;
            public UInt64 WriteTransferCount;
            public UInt64 OtherTransferCount;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct JOBOBJECT_EXTENDED_LIMIT_INFORMATION
        {
            public JOBOBJECT_BASIC_LIMIT_INFORMATION BasicLimitInformation;
            public IO_COUNTERS IoInfo;
            public UIntPtr ProcessMemoryLimit;
            public UIntPtr JobMemoryLimit;
            public UIntPtr PeakProcessMemoryUsed;
            public UIntPtr PeakJobMemoryUsed;
        }

        public enum CpuFlags : UInt32
        {
            JOB_OBJECT_CPU_RATE_CONTROL_ENABLE = 0x00000001,
            JOB_OBJECT_CPU_RATE_CONTROL_WEIGHT_BASED = 0x00000002,
            JOB_OBJECT_CPU_RATE_CONTROL_HARD_CAP = 0x00000004
        }

        // https://stackoverflow.com/a/31361144
        [StructLayout(LayoutKind.Explicit)]
        //[CLSCompliant(false)]
        public struct JOBOBJECT_CPU_RATE_CONTROL_INFORMATION
        {
            [FieldOffset(0)]
            public CpuFlags ControlFlags;
            [FieldOffset(4)]
            public UInt32 CpuRate;
            [FieldOffset(4)]
            public UInt32 Weight;
        }

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
        public static extern IntPtr CreateJobObject(IntPtr lpJobAttributes, string name);

        [DllImport("kernel32.dll")]
        internal static extern bool SetInformationJobObject(IntPtr job, JobObjectInfoType infoType,
            ref JOBOBJECT_EXTENDED_LIMIT_INFORMATION lpJobObjectInfo, uint cbJobObjectInfoLength);

        [DllImport("kernel32.dll")]
        internal static extern bool SetInformationJobObject(IntPtr job, JobObjectInfoType infoType,
            ref JOBOBJECT_CPU_RATE_CONTROL_INFORMATION lpJobObjectInfo, uint cbJobObjectInfoLength);

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern bool AssignProcessToJobObject(IntPtr job, IntPtr process);
    }

    public class JobUtils
    {
        ///
        public static void SetExtendedLimitInformationJobObject(IntPtr jobHandle, JOBOBJECT_EXTENDED_LIMIT_INFORMATION extendedInfo)
        {
            int length = Marshal.SizeOf(typeof(JOBOBJECT_EXTENDED_LIMIT_INFORMATION));

            if (!Win32.SetInformationJobObject(jobHandle, JobObjectInfoType.ExtendedLimitInformation,
                ref extendedInfo, (uint)length))
            {
                throw new Win32Exception();
            }
        }


        ///
        public static void SetCpuRateControlInformationJobObject(IntPtr jobHandle, JOBOBJECT_CPU_RATE_CONTROL_INFORMATION cpuRateControlInformation)
        {
            int length = Marshal.SizeOf(typeof(JOBOBJECT_CPU_RATE_CONTROL_INFORMATION));

            if (!Win32.SetInformationJobObject(jobHandle, JobObjectInfoType.JobObjectCpuRateControlInformation,
                ref cpuRateControlInformation, (uint)length))
            {
                throw new Win32Exception();
            }
        }

        ///
        public static void AssignProcessToJobObject(IntPtr job, Process process)
        {
            bool success = Win32.AssignProcessToJobObject(job, process.Handle);

            if (!success && !process.HasExited)
                throw new Win32Exception();
        }
    }


                // test code
                var cpuLimit = 20; // 20%
                var job = Win32.CreateJobObject(IntPtr.Zero, null);
                JobUtils.SetCpuRateControlInformationJobObject(job, new Win32.JOBOBJECT_CPU_RATE_CONTROL_INFORMATION
                {
                    ControlFlags = Win32.CpuFlags.JOB_OBJECT_CPU_RATE_CONTROL_ENABLE | Win32.CpuFlags.JOB_OBJECT_CPU_RATE_CONTROL_HARD_CAP,
                    CpuRate = (uint)cpuLimit * 100
                });
                JobUtils.AssignProcessToJobObject(job, Process.GetCurrentProcess());

Answer 3

操作系统应该处理两个应用程序之间的时间共享。您的应用程序使用 100% 的 CPU 可能是有充分理由的，它正在计算一些东西。如果您需要等待另一个进程的完成，那么您可以使用Process.WaitForExit在另一个进程完成时停止调用线程的执行。