Provides a basic performance measuring in MVC for each rendered action.

ASP.NET MVC performance attribute

public class StopwatchActionFilter : ActionFilterAttribute
{
	private readonly Dictionary<string, Stopwatch> _stopWatches;

	public StopwatchActionFilter()
	{
		if (_stopWatches == null)
			_stopWatches = new Dictionary<string, Stopwatch>();
	}

	public override void OnActionExecuting(ActionExecutingContext filterContext) {
		//Gets currently executing action and controller
		string actionName = filterContext.RequestContext.RouteData.Values["Action"].ToString();
		string controllerName = filterContext.RequestContext.RouteData.Values["Controller"].ToString();

		string key = String.Format("NC-{0}-{1}", controllerName, actionName);
		if (_stopWatches.ContainsKey(key))
			_stopWatches[key].Reset();
		else
			_stopWatches.Add(key, new Stopwatch());
		_stopWatches[key].Start();
		base.OnActionExecuting(filterContext);
	}

	public override void OnActionExecuted(ActionExecutedContext filterContext) {
		string actionName = filterContext.RequestContext.RouteData.Values["Action"].ToString();
		string controllerName = filterContext.RequestContext.RouteData.Values["Controller"].ToString();

		string key = String.Format("NC-{0}-{1}", controllerName, actionName);
		if (_stopWatches.ContainsKey(key)){
			_stopWatches[key].Stop();
			try{
				filterContext.HttpContext.Response.AddHeader(key , _stopWatches[key].ElapsedMilliseconds.ToString() + "ms");
			}catch{}
		}
		base.OnActionExecuted(filterContext);
	}

}