多次调用同一个过程效率下降的问题

Public Class 公共类

    Declare Function GetTickCount Lib "kernel32.dll" Alias "GetTickCount" () As Integer

    Public Sub 循环()

        Dim 次数 As Integer = 0
        Dim Start_T = GetTickCount

        Do While True

              Threading.Thread.Sleep(100)

               '做点事占用点时间

              次数 += 1

              If 次数 = 50 Then

                        Dim Stop_T = GetTickCount

                        Console.WriteLine("运行50次所用时间(毫秒):{0}", Stop_T - Start_T)

                        次数 = 0

                        Start_T = GetTickCount

              End If

        Loop

    End Sub

End Class

调用时用多线程时：

 Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

            Dim ggl As New 公共类

            Dim Thread1 As New System.Threading.Thread(New Threading.ParameterizedThreadStart(AddressOf ggl.循环))

           Thread1.IsBackground = True

            Thread1.Start() ' 启动新线程

End Sub

结果前面2次运行时运行速度正常，当运行超过5个线程时，运行速度明显变慢。等待解决方案