Ahm*_*laf 6 c# floating-point double performance long-integer
以下代码的令人惊讶的输出显示double上的算术比long更快100%:
Test_DivOperator Float算术测量时间:15974.5024 ms.
Test_DivOperator整数算术测量时间:28548.183 ms.
使用的构建设置是.Net4.5 C#5.0(平台目标:x64)
使用的硬件是Intel Core i5-2520M(运行Windows7 64Bit)
注意:使用的运算符(此处为除法)确实会影响结果,除法最大化此观察结果
const int numOfIterations = 1; //this value takes memory access out of the game
const int numOfRepetitions = 500000000; //CPU bound application
Random rand = new Random();
double[] Operand1 = new double[numOfIterations];
double[] Operand2 = new double[numOfIterations];
double[] Operand3 = new double[numOfIterations];
long[] Int64Operand1 = new long[numOfIterations];
long[] Int64Operand2 = new long[numOfIterations];
long[] Int64Operand3 = new long[numOfIterations];
for (int i = 0; i < numOfIterations; i++)
{
Operand1[i]=(rand.NextDouble() * 100);
Operand2[i]=(rand.NextDouble() * 80);
Operand3[i]=(rand.NextDouble() * 17);
Int64Operand1[i] = (long)Operand1[i];
Int64Operand2[i] = (long)Operand2[i]+1;
Int64Operand3[i] = (long)Operand3[i]+1;
}
double[] StdResult = new double[numOfIterations];
long[] NewResult = new long[numOfIterations];
TimeSpan begin = Process.GetCurrentProcess().TotalProcessorTime;
for (int j = 0; j < numOfRepetitions; j++)
{
for (int i = 0; i < numOfIterations; i++)
{
double result = Operand1[i] / Operand2[i];
result = result / Operand3[i];
StdResult[i]=(result);
}
}
TimeSpan end = Process.GetCurrentProcess().TotalProcessorTime;
Console.WriteLine("Test_DivOperator Float arithmetic measured time: " + (end - begin).TotalMilliseconds + " ms.");
begin = Process.GetCurrentProcess().TotalProcessorTime;
for (int j = 0; j < numOfRepetitions; j++)
{
for (int i = 0; i < numOfIterations; i++)
{
long result = Int64Operand1[i] / Int64Operand2[i];
result = result / Int64Operand3[i];
NewResult[i]=(result);
}
}
end = Process.GetCurrentProcess().TotalProcessorTime;
Console.WriteLine("Test_DivOperator Integer arithmetic measured time: " + (end - begin).TotalMilliseconds + " ms.");