如何在c#中测量给定进程的CPU周期
本文关键字：进程 CPU 周期 测量 | 更新日期: 2023-09-27 18:15:20
我有一些不同的模型，它们使用不同的算法执行相同的任务。我想通过测量CPU周期来比较这些模型的性能(我尝试使用System.Diagnostics.StopWatch来计数Ticks，但结果不够准确)。
我发现了一个类，通过使用P/Invoke测量CPU周期，如下所示:
IModel model;
CodeTimer.Time(true, model.ToString(), totalTime, model.TimeStep);
上面的方法用N乘以model.TimeStep迭代。我注意到CodeTimer.Time的结果差异很大(从58 KCycles到890 KCycles，至少相差一个数量级)。因此，如果我错了，请纠正我，但是由于CodeTimer类标记了进程前后的周期，它还可以计算在执行model.TimeStep方法(我想测量性能的方法)期间发生的任何其他进程(甚至操作系统进程)使用的周期。
两个问题:
- 我的上述假设正确吗?如果是，那么我需要提出另一种解决方案来测量CPU周期，这导致了我的主要问题:
System.Threading.Thread中迭代model.TimeStep()并使用QueryProcessCycleTime测量给定线程的周期的想法。然而，由于QueryProcessCycleTime接收作为输入的System.Threading.WaitHandle(或IntPtr)，我不知道如何告诉这个方法，我想测量我刚刚创建的特定Thread的周期。换句话说，我不知道如何把我创建的thread放在一起迭代模型，WaitHandle和QueryProcessCycleTime，即使我读过一些使用WaitHandle的例子(我只是不能把所有东西混合在一起)。
应该是这样的:
class ModelSimulator
{
public Model1 model1 { get; private set; } // implements IModel
public Model2 model2 { get; private set; } // implements IModel
/* other methods */
public void RunModel(object obj)
{
IModel model = (IModel)obj;
Int32 t = model.maxTime;
while (t-- > 0)
model.TimeStep();
}
}
在main方法中，我做:
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern Boolean QueryProcessCycleTime(SafeWaitHandle processHandle, out UInt64 CycleTime);
static void Main(string[] args)
{
ModelSimulator ms = new ModelSimulator();
Thread thread = new Thread(ms.RunModel);
thread.Start(ms.model1);
// here I start the thread, but how can I use QueryProcessCycleTime to measure
// the thread execution
}
PS:我的不是这个问题的重复，因为我需要一些更具体的答案，这是不存在的…我的问题可以作为你问题的补充。
根据@ShlomiBorovitz的建议，可以使用GetCurrentThread()来识别正在运行进程的Thread。可能的解决方案是在CodeTimer.cs中进行非常简单的修改。需要的修改可以在这个答案的末尾找到。我添加了一个名为PerformanceStatus的类，以便在用于测量性能的CodeTimer.Time()方法的结果中显示级别0、1和2的垃圾收集量。因此，还可以知道Garbage Collector在进程中是否收集了任何东西。
你只需要像这样使用它:
ModelSimulator nm = new ModelSimulator();
CodeTimer c = new CodeTimer(nm.RunModel, model); // model implements IModel
UInt64 time = c.Time().CPUCycles;
Console.WriteLine("{0:0.000e+000} KCy", (Double)time / 1000.0D);
使得问题中给出了类ModelSimulator，并带有一个方法ModelSimulator.RunModel(IModel model)，该方法接收一个类型为IModel的对象。
这是衡量性能所需的CodeTimer.cs
public sealed class CycleTime
{
private Boolean m_trackingThreadTime;
private SafeWaitHandle m_handle;
private UInt64 m_startCycleTime;
private CycleTime(Boolean trackingThreadTime, SafeWaitHandle handle)
{
m_trackingThreadTime = trackingThreadTime;
m_handle = handle;
m_startCycleTime = m_trackingThreadTime ? Thread() : Process(m_handle);
}
[CLSCompliant(false)]
public UInt64 Elapsed()
{
UInt64 now = m_trackingThreadTime ? Thread(/*m_handle*/) : Process(m_handle);
return now - m_startCycleTime;
}
public static CycleTime StartThread(SafeWaitHandle threadHandle)
{
return new CycleTime(true, threadHandle);
}
public static CycleTime StartProcess(SafeWaitHandle processHandle)
{
return new CycleTime(false, processHandle);
}
public static UInt64 Thread(IntPtr threadHandle)
{
UInt64 cycleTime;
if (!QueryThreadCycleTime(threadHandle, out cycleTime))
throw new Win32Exception();
return cycleTime;
}
/// <summary>
/// Retrieves the cycle time for the specified thread.
/// </summary>
/// <param name="threadHandle">Identifies the thread whose cycle time you'd like to obtain.</param>
/// <returns>The thread's cycle time.</returns>
[CLSCompliant(false)]
public static UInt64 Thread(SafeWaitHandle threadHandle)
{
UInt64 cycleTime;
if (!QueryThreadCycleTime(threadHandle, out cycleTime))
throw new Win32Exception();
return cycleTime;
}
[CLSCompliant(false)]
public static UInt64 Thread()
{
UInt64 cycleTime;
if (!QueryThreadCycleTime((IntPtr)(-2), out cycleTime))
throw new Win32Exception();
return cycleTime;
}
/// <summary>
/// Retrieves the sum of the cycle time of all threads of the specified process.
/// </summary>
/// <param name="processHandle">Identifies the process whose threads' cycles times you'd like to obtain.</param>
/// <returns>The process' cycle time.</returns>
[CLSCompliant(false)]
public static UInt64 Process(SafeWaitHandle processHandle)
{
UInt64 cycleTime;
if (!QueryProcessCycleTime(processHandle, out cycleTime))
throw new Win32Exception();
return cycleTime;
}
/// <summary>
/// Retrieves the cycle time for the idle thread of each processor in the system.
/// </summary>
/// <returns>The number of CPU clock cycles used by each idle thread.</returns>
[CLSCompliant(false)]
public static UInt64[] IdleProcessors()
{
Int32 byteCount = Environment.ProcessorCount;
UInt64[] cycleTimes = new UInt64[byteCount];
byteCount *= 8; // Size of UInt64
if (!QueryIdleProcessorCycleTime(ref byteCount, cycleTimes))
throw new Win32Exception();
return cycleTimes;
}
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern Boolean QueryThreadCycleTime(IntPtr threadHandle, out UInt64 CycleTime);
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern Boolean QueryThreadCycleTime(SafeWaitHandle threadHandle, out UInt64 CycleTime);
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern Boolean QueryProcessCycleTime(SafeWaitHandle processHandle, out UInt64 CycleTime);
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern Boolean QueryIdleProcessorCycleTime(ref Int32 byteCount, UInt64[] CycleTimes);
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
public static extern IntPtr GetCurrentThread();
}
public sealed class CodeTimer //: IDisposable
{
private Int32 m_collectionCount0;
private Int32 m_collectionCount1;
private Int32 m_collectionCount2;
private Thread m_thread;
private IModel m_model;
private Action<IModel> m_performanceMethod;
private UInt64 outThreadCycles;
public CodeTimer(Action<IModel> perfMethod, IModel model)
{
PrepareForOperation();
m_performanceMethod = perfMethod;
m_model = model;
m_thread = new Thread(PerformanceTest);
}
private void PerformanceTest()
{
PrepareForOperation();
IntPtr p = CycleTime.GetCurrentThread();
UInt64 t = CycleTime.Thread(p);
m_performanceMethod(m_model);
outThreadCycles = CycleTime.Thread(p) - t;
}
public PerformanceStatus Time()
{
m_thread.Start();
m_thread.Join();
return new PerformanceStatus(GC.CollectionCount(0) - m_collectionCount0, GC.CollectionCount(1) - m_collectionCount1, GC.CollectionCount(2) - m_collectionCount2, outThreadCycles);
}
private void PrepareForOperation()
{
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
m_collectionCount0 = GC.CollectionCount(0);
m_collectionCount1 = GC.CollectionCount(1);
m_collectionCount2 = GC.CollectionCount(2);
}
}
public class PerformanceStatus
{
public Int32 GCCount1;
public Int32 GCCount2;
public Int32 GCCount3;
public UInt64 CPUCycles;
public PerformanceStatus(Int32 gc1, Int32 gc2, Int32 gc3, UInt64 cpuCycles)
{
this.GCCount1 = gc1;
this.GCCount2 = gc2;
this.GCCount3 = gc3;
this.CPUCycles = cpuCycles;
}
}