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High Precision Timer in .NET/C#

Posted by hakanl in Uncategorized on January 29, 2013

Here’s a high-precision timer I wrote. I get roughly <1ms avg precision on 25ms interval. But if Windows is busy it may come in late. It’s fairly lean on CPU utilization. Feel free to use. It uses Sleep(1) when the next tick is more than 15ms away and then SpinUntil (which yields as needed) to keep CPU usage at bay. Uses .NET4 features.

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	using NLog;
	using System;
	using System.Linq;
	using System.Threading;
	using System.Threading.Tasks;

	namespace Animatroller.Framework.Utility
	{
	public class HighPrecisionTimer : IDisposable
	{
	public class TickEventArgs : EventArgs
	{
	public TimeSpan Duration { get; private set; }
	public long TotalTicks { get; private set; }

	public TickEventArgs(TimeSpan totalDuration, long totalTicks)
	{
	this.Duration = totalDuration;
	this.TotalTicks = totalTicks;
	}
	}

	protected static Logger log = LogManager.GetCurrentClassLogger();
	public event EventHandler<TickEventArgs> Tick;
	protected CircularBuffer.CircularBuffer<int> tickTiming;
	protected CancellationTokenSource cancelSource;

	public HighPrecisionTimer(int interval)
	{
	log.Info("Starting HighPrecisionTimer with {0} ms interval", interval);

	if (interval < 1)
	throw new ArgumentOutOfRangeException();
	System.Diagnostics.Trace.Assert(interval >= 10, "Not reliable/tested, may use too much CPU");

	cancelSource = new CancellationTokenSource();

	// Used to report timing accuracy for 1 sec, running total
	tickTiming = new CircularBuffer.CircularBuffer<int>(1000 / interval, true);

	var watch = System.Diagnostics.Stopwatch.StartNew();
	long durationMs = 0;
	long totalTicks = 0;
	long nextStop = interval;
	long lastReport = 0;

	var task = new Task(() =>
	{
	while (!this.cancelSource.IsCancellationRequested)
	{
	long msLeft = nextStop - watch.ElapsedMilliseconds;
	if (msLeft <= 0)
	{
	durationMs = watch.ElapsedMilliseconds;
	totalTicks = durationMs / interval;

	tickTiming.Put((int)(durationMs - nextStop));

	if (durationMs - lastReport >= 1000)
	{
	// Report
	log.Debug("Last second - avg: {0:F1} best: {1} worst: {2}",
	tickTiming.Average(), tickTiming.Min(), tickTiming.Max());

	lastReport = durationMs;
	}

	var handler = Tick;
	if (handler != null)
	handler(this, new TickEventArgs(TimeSpan.FromMilliseconds(durationMs), totalTicks));

	// Calculate when the next stop is. If we're too slow on the trigger then we'll skip ticks
	nextStop = interval * (watch.ElapsedMilliseconds / interval + 1);
	}
	else if (msLeft < 16)
	{
	System.Threading.SpinWait.SpinUntil(() => watch.ElapsedMilliseconds >= nextStop);
	continue;
	}

	System.Threading.Thread.Sleep(1);
	}
	}, cancelSource.Token, TaskCreationOptions.LongRunning);

	task.Start();
	}

	public void Dispose()
	{
	this.cancelSource.Cancel();
	}
	}
	}

view raw HighPrecisionTimer hosted with ❤ by GitHub

#, .NET, C#, cpu utilization, net4, precision timer, Timer

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