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Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.

How to: Use the High-Resolution Timer

.NET Framework 3.5

Some devices support a high-resolution timer. This timer, when present, provides more precise measurements than you can obtain by using the TickCount property, which has a 1-millisecond resolution. In applications where precise time measurements are important, the high-resolution timer provides the best results. For example, some Direct3D applications display more smoothly when the animation is based on the high-resolution timer. You can also use this timer in an application to determine how much time a method or a section of code requires to execute.

This code example provides a class that makes it easier to use the high-resolution timer in managed code on Windows CE. The example has the following features:

  • Platform invoke declarations for the native methods in Windows CE.

  • A property that is used to get the frequency of the high-resolution counter.

  • A property that is used to get the value of the high-resolution counter.

  • An implementation that supports the TickCount property as a fallback if the QueryPerformanceCounter function is not supported or is emulated.

  • An example of how the high-resolution counter can be used to time an operation.

public class HiResTimer
{
    private bool isPerfCounterSupported = false;
    private Int64 frequency = 0;

    // Windows CE native library with QueryPerformanceCounter(). 
    private const string lib = "coredll.dll";
    [DllImport(lib)]
    private static extern int QueryPerformanceCounter(ref Int64 count);
    [DllImport(lib)]
    private static extern int QueryPerformanceFrequency(ref Int64 frequency);

    public HiResTimer()
    {
        // Query the high-resolution timer only if it is supported. 
        // A returned frequency of 1000 typically indicates that it is not 
        // supported and is emulated by the OS using the same value that is 
        // returned by Environment.TickCount. 
        // A return value of 0 indicates that the performance counter is 
        // not supported. 
        int returnVal = QueryPerformanceFrequency(ref frequency);

        if (returnVal != 0 && frequency != 1000)
        {
            // The performance counter is supported.
            isPerfCounterSupported = true;
        }
        else
        {
            // The performance counter is not supported. Use 
            // Environment.TickCount instead.
            frequency = 1000;
        }
    }

    public Int64 Frequency
    {
        get
        {
            return frequency;
        }
    }

    public Int64 Value
    {
        get
        {
            Int64 tickCount = 0;

            if (isPerfCounterSupported)
            {
                // Get the value here if the counter is supported.
                QueryPerformanceCounter(ref tickCount);
                return tickCount;
            }
            else
            {
                // Otherwise, use Environment.TickCount. 
                return (Int64)Environment.TickCount;
            }
        }
    }

    static void Main()
    {
        HiResTimer timer = new HiResTimer();

        // This example shows how to use the high-resolution counter to  
        // time an operation.  

        // Get counter value before the operation starts.
        Int64 counterAtStart = timer.Value;

        // Perform an operation that takes a measureable amount of time. 
        for (int count = 0; count < 10000; count++)
        {
            count++;
            count--;
        }

        // Get counter value when the operation ends.
        Int64 counterAtEnd = timer.Value;

        // Get time elapsed in tenths of a millisecond.
        Int64 timeElapsedInTicks = counterAtEnd - counterAtStart;
        Int64 timeElapseInTenthsOfMilliseconds =
            (timeElapsedInTicks * 10000) / timer.Frequency;

        MessageBox.Show("Time Spent in operation (tenths of ms) "
                       + timeElapseInTenthsOfMilliseconds +
                       "\nCounter Value At Start: " + counterAtStart +
                       "\nCounter Value At End : " + counterAtEnd +
                       "\nCounter Frequency : " + timer.Frequency);
    }
}

This example requires references to the following namespaces:

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