Kernel Timer für Performancetests

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78

using System;
using System.Runtime.InteropServices;

namespace OperationalManagement
{
	/// <summary>
	/// FxCop Rule CA1060.
	/// This type contains members with the DllImport attribute. 
	/// Members with the DllImport attribute should be contained 
	/// in classes named NativeMethods, SafeNativeMethods, 
	/// or UnsafeNativeMethods.
	/// </summary>
	internal sealed class NativeMethods
	{
		/// <summary>
		/// private Ctor for static Class.
		/// </summary>
		private NativeMethods()
		{
		}

		/// <summary>
		/// DllImport von KERNEL32.
		/// </summary>
		/// <param name="nPfCt">Performancecounter.</param>
		/// <returns>true oder false.</returns>
		[DllImport("KERNEL32")]
		[return : MarshalAs(UnmanagedType.Bool)]
		internal static extern bool QueryPerformanceCounter(ref Int64 nPfCt);

		/// <summary>
		/// DllImport von KERNEL32.
		/// </summary>
		/// <param name="nPfFreq">Ferequenz.</param>
		/// <returns>true oder false.</returns>
		[DllImport("KERNEL32")]
		[return : MarshalAs(UnmanagedType.Bool)]
		internal static extern bool QueryPerformanceFrequency(ref Int64 nPfFreq);
	}

	/// <summary>
	/// For Performancetestings
	/// </summary>
	public sealed class KernelTimer
	{
		private Int64 _i64Frequency;
		private Int64 _i64Start;

		/// <summary>
		/// startet den Timer
		/// </summary>
		public void Start()
		{
			Reset();
			NativeMethods.QueryPerformanceCounter(ref _i64Start);
		}

		/// <summary>
		/// Zurücksetzen
		/// </summary>
		public void Reset()
		{
			NativeMethods.QueryPerformanceFrequency(ref _i64Frequency);
			_i64Start = 0;
		}

		/// <summary>
		/// stopt den Timer und liefert das Resultat
		/// </summary>
		/// <returns>double-Wert.</returns>
		public double End()
		{
			Int64 i64End = 0;
			NativeMethods.QueryPerformanceCounter(ref i64End);
			return ((i64End - _i64Start)/(double) _i64Frequency);
		}
	}
}