性能《.net 框架程序设计》里的几句代码,我重新整理了一下,写成函数,这样下面的反编译代码看起来更方便点:
public void Boxing()
        {
            Int32 v = 5;
            Console.WriteLine("{0},{1},{2}",v,v,v);
        }
        public void Boxing1()
        {
            Int32 v = 5;
            object o = v;
            Console.WriteLine("{0},{1},{2}",o,o,o);
        }两个函数的输出结果是一样的,但是哪一个函数更好呢?
第一个显然更简单,但是在性能上第二个好,看看反编译的代码:
Boxing函数:
.method public hidebysig instance void Boxing() cil managed
{
      // Code Size: 31 byte(s)
      .maxstack 4
      .locals (
            int32 V_0)
      L_0000: ldc.i4.5 
      L_0001: stloc.0 
      L_0002: ldstr "{0},{1},{2}"
      L_0007: ldloc.0 
      L_0008: box int32
      L_000d: ldloc.0 
      L_000e: box int32
      L_0013: ldloc.0 
      L_0014: box int32
      L_0019: call void [mscorlib]System.Console::WriteLine(string, object, object, object)
      L_001e: ret 
}
 
Boxing1函数的:
.method public hidebysig instance void Boxing1() cil managed
{
      // Code Size: 23 byte(s)
      .maxstack 4
      .locals (
            int32 V_0,
            object V_1)
      L_0000: ldc.i4.5 
      L_0001: stloc.0 
      L_0002: ldloc.0 
      L_0003: box int32
      L_0008: stloc.1 
      L_0009: ldstr "{0},{1},{2}"
      L_000e: ldloc.1 
      L_000f: ldloc.1 
      L_0010: ldloc.1 
      L_0011: call void [mscorlib]System.Console::WriteLine(string, object, object, object)
      L_0016: ret 
}
第一个函数有三次装箱操作,第二个只有一次,在内存和时间消耗上都要小些。
                   
简单代码的性能差异
                    80酷酷网    80kuku.com 
       
  
 
 
  
