Why GetThreadTimes Returns

Question

I'm trying to measure the time spent in a thread for the purpose of a progress report, but I get very strange results from the GetThreadTimes system call. Given the following program (compiled in VS 2013, oriented to .NET 4.5):

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;

namespace ThreadTimingTest
{
    class Program
    {
        static Stopwatch _wallClockTimer;

        static System.Timers.Timer _timer = new System.Timers.Timer();

        private static Thread _thread;
        private static IntPtr _threadHandle;

        static void Main(string[] args)
        {
            _timer = new System.Timers.Timer();
            _timer.Elapsed += (s, e) =>
            {
                System.Runtime.InteropServices.ComTypes.FILETIME start, end, rawKernelTime, rawUserTime;

                GetThreadTimes(_threadHandle, out start, out end, out rawKernelTime, out rawUserTime);

                //ref: http://stackoverflow.com/a/6083846
                ulong uLow = (ulong)rawKernelTime.dwLowDateTime;
                ulong uHigh = (uint)rawKernelTime.dwHighDateTime;
                uHigh = uHigh << 32;
                long kernelTime = (long)(uHigh | uLow);

                uLow = (ulong)rawUserTime.dwLowDateTime;
                uHigh = (uint)rawUserTime.dwHighDateTime;
                uHigh = uHigh << 32;
                long userTime = (long)(uHigh | uLow);

                Debug.WriteLine("Kernel time: " + kernelTime);
                Debug.WriteLine("User time: " + userTime);
                Debug.WriteLine("Combined raw execution time: " + (kernelTime + userTime));

                long elapsedMilliseconds = (kernelTime + userTime) / 10000; //convert to milliseconds: raw timing unit is 100 nanoseconds
                Debug.WriteLine("Elapsed thread time: " + elapsedMilliseconds + " milliseconds");

                Debug.WriteLine("Wall Clock Time: " + _wallClockTimer.ElapsedMilliseconds + " milliseconds");

            };

            _timer.Interval = 1000;

            _wallClockTimer = new Stopwatch();

            Debug.WriteLine("Starting...");
            RunTest();

            Debug.WriteLine("Ended.");
        }

        public static void RunTest()
        {
            _thread =
                new Thread
                (
                    () =>
                    {
                        _threadHandle = GetCurrentThread();
                        Stopwatch sw = Stopwatch.StartNew();

                        while (sw.ElapsedMilliseconds < 3000)
                        {
                            int i = 1 + 2;
                        } //do busy-work for 3 seconds

                        sw.Stop();
                    }
                );

            _timer.Start();

            _thread.Start();a

            _wallClockTimer.Start();

            _thread.Join();
        }

        [DllImport("kernel32.dll", SetLastError = true)]
        static extern bool GetThreadTimes(IntPtr hThread,
            out System.Runtime.InteropServices.ComTypes.FILETIME lpCreationTime, out System.Runtime.InteropServices.ComTypes.FILETIME lpExitTime,
            out System.Runtime.InteropServices.ComTypes.FILETIME lpKernelTime, out System.Runtime.InteropServices.ComTypes.FILETIME lpUserTime);

        [DllImport("kernel32.dll")]
        private static extern IntPtr GetCurrentThread();
    }
}

I get the following output:

Starting...
Kernel time: 0
User time: 0
Combined raw execution time: 0
Elapsed thread time: 0 milliseconds
Wall Clock Time: 1036 milliseconds
Kernel time: 0
User time: 0
Combined raw execution time: 0
Elapsed thread time: 0 milliseconds
Wall Clock Time: 2036 milliseconds
The thread '<No Name>' (0x191c) has exited with code 0 (0x0).
Ended.

I would expect it to GetThreadTimesreport something other than zero during the stream: why is zero indicated?

Answer 1

After creating a pair of simple mods to your code based on the link provided by Hans, the actual time values ​​are displayed.

Adding multiple interop declarations:

[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool DuplicateHandle(IntPtr hSourceProcessHandle,
    IntPtr hSourceHandle, IntPtr hTargetProcessHandle, out IntPtr lpTargetHandle,
    uint dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, uint dwOptions);

[Flags]
public enum DuplicateOptions : uint
{
    DUPLICATE_CLOSE_SOURCE = (0x00000001), // Closes the source handle. This occurs regardless of any error status returned.
    DUPLICATE_SAME_ACCESS = (0x00000002),  // Ignores the dwDesiredAccess parameter. The duplicate handle has the same access as the source handle.
}

[DllImport("kernel32.dll")]
static extern IntPtr GetCurrentProcess();

:

//_threadHandle = GetCurrentThread();       <-- previous assignment
IntPtr processHandle = GetCurrentProcess();
bool result = DuplicateHandle(processHandle, GetCurrentThread(), processHandle, out _threadHandle, 0, false, (uint) DuplicateOptions.DUPLICATE_SAME_ACCESS);

:

Starting...
Kernel time: 0
User time: 10000000
Combined raw execution time: 10000000
Elapsed thread time: 1000 milliseconds
Wall Clock Time: 1006 milliseconds
Kernel time: 0
User time: 20000000
Combined raw execution time: 20000000
Elapsed thread time: 2000 milliseconds
Wall Clock Time: 2004 milliseconds
Kernel time: 0
User time: 30000000
Combined raw execution time: 30000000
Ended.
Elapsed thread time: 3000 milliseconds
Wall Clock Time: 3045 milliseconds

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