基础才是重中之重~老赵写的CodeTimer是代码性能测试的利器

转自：/article/4624210.html

ForegroundColor;

45 Console.ForegroundColor = ConsoleColor.Yellow;

46 Console.WriteLine(name);

47

48 // 2. Record the latest GC counts

49 //GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);

50 GC.Collect(GC.MaxGeneration);

51 int[] gcCounts = new int[GC.MaxGeneration + 1];

52 for (int i = 0; i <= GC.MaxGeneration; i++)

53 {

54 gcCounts[i] = GC.CollectionCount(i);

55 }

56

57 // 3. Run action

58 Stopwatch watch = new Stopwatch();

59 watch.Start();

60 long ticksFst = GetCurrentThreadTimes(); //100 nanosecond one tick

61 for (int i = 0; i < iteration; i++) action();

62 long ticks = GetCurrentThreadTimes() - ticksFst;

63 watch.Stop();

64

65 // 4. Print CPU

66 Console.ForegroundColor = currentForeColor;

67 Console.WriteLine("\tTime Elapsed:\t\t" +

68 watch.ElapsedMilliseconds.ToString("N0") + "ms");

69 Console.WriteLine("\tTime Elapsed (one time):" +

70 (watch.ElapsedMilliseconds / iteration).ToString("N0") + "ms");

71 Console.WriteLine("\tCPU time:\t\t" + (ticks * 100).ToString("N0")

72 + "ns");

73 Console.WriteLine("\tCPU time (one time):\t" + (ticks * 100 /

74 iteration).ToString("N0") + "ns");

75

76 // 5. Print GC

77 for (int i = 0; i <= GC.MaxGeneration; i++)

78 {

79 int count = GC.CollectionCount(i) - gcCounts[i];

80 Console.WriteLine("\tGen " + i + ": \t\t\t" + count);

81 }

82 Console.WriteLine();

83 }

84

85

86

87 public static void Time(string name, int iteration, IAction action)

88 {

89 if (String.IsNullOrEmpty(name))

90 {

91 return;

92 }

93

94 if (action == null)

95 {

96 return;

97 }

98

99 //1. Print name

100 ConsoleColor currentForeColor = Console.ForegroundColor;

101 Console.ForegroundColor = ConsoleColor.Yellow;

102 Console.WriteLine(name);

103

104 // 2. Record the latest GC counts

105 //GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);

106 GC.Collect(GC.MaxGeneration);

107 int[] gcCounts = new int[GC.MaxGeneration + 1];

108 for (int i = 0; i <= GC.MaxGeneration; i++)

109 {

110 gcCounts[i] = GC.CollectionCount(i);

111 }

112

113 // 3. Run action

114 Stopwatch watch = new Stopwatch();

115 watch.Start();

116 long ticksFst = GetCurrentThreadTimes(); //100 nanosecond one tick

117 for (int i = 0; i < iteration; i++) action.Action();

118 long ticks = GetCurrentThreadTimes() - ticksFst;

119 watch.Stop();

120

121 // 4. Print CPU

122 Console.ForegroundColor = currentForeColor;

123 Console.WriteLine("\tTime Elapsed:\t\t" +

124 watch.ElapsedMilliseconds.ToString("N0") + "ms");

125 Console.WriteLine("\tTime Elapsed (one time):" +

126 (watch.ElapsedMilliseconds / iteration).ToString("N0") + "ms");

127 Console.WriteLine("\tCPU time:\t\t" + (ticks * 100).ToString("N0")

128 + "ns");

129 Console.WriteLine("\tCPU time (one time):\t" + (ticks * 100 /

130 iteration).ToString("N0") + "ns");

131

132 // 5. Print GC

133 for (int i = 0; i <= GC.MaxGeneration; i++)

134 {

135 int count = GC.CollectionCount(i) - gcCounts[i];

136 Console.WriteLine("\tGen " + i + ": \t\t\t" + count);

137 }

138 Console.WriteLine();

139 }

140 }

有了上面的codeTimer我们就来测试一个吧，如字条串和并的问题，用+=还是用StringBuilder呢，有点经验的程序员肯定说是StringBuilder，是的，确实是后者，那我们就来看看这

两种方法测试的结果吧

1 CodeTimer.Time("String Concat", 100000,

2 () =>

3 {

4 var s = "1";

5 for (int i = 1; i < 10; i++)

6 s = s + "1";

7 });

8

9 CodeTimer.Time("StringBuilder Concat", 100000,

10 () =>

11 {

12 var s = new StringBuilder();

13 for (int i = 1; i < 10; i++)

14 s.Append("1");

15 });

测试的结果如下：

从图中我们可以看到StringBuilder快的很明显，无论是执行时间，还是对CPU的消耗及GC回收都远低于String的拼结，所以，才有以下结论：

在字符串拼结时，请使用StringBuilder吧！