C#比較dynamic和Dictionary性能
開發(fā)中需要傳遞變參,考慮使用 dynamic 還是 Dictionary(準確地說是Dictionary<string,object>)。dynamic 的編碼體驗顯著優(yōu)于 Dictionary,如果性能差距不大的話,我會選擇使用dynamic。搜索后沒有找到類似對比數(shù)據(jù),決定自行實驗。
首先使用以下測試代碼:
- public void TestDynamic()
- {
- var e = CallDynamic(new { Value = 0 });
- int v = e.Value;
- }
- public void TestDictionary()
- {
- var dict = new Dictionary<string, object>();
- dict["Value"] = 0;
- dict = CallDictionary(dict);
- int v = (int)dict["Value"];
- }
- private dynamic CallDynamic(dynamic test)
- {
- int v = test.Value;
- v++;
- return new { Value = v };
- }
- private Dictionary<string, object> CallDictionary(
- Dictionary<string, object> test)
- {
- int v = (int)test["Value"];
- v++;
- var dict = new Dictionary<string, object>();
- dict["Value"] = v;
- return dict;
- }
分別比較運行 1次、10次、100次、1000次、1e4次、1e5次、1e6次 時間
結(jié)果:
其中dynamic列和dynamic2列的數(shù)據(jù)分別是:
在一次運行中執(zhí)行一步測試 和 在一次運行中連續(xù)執(zhí)行所有測試
分析測試過程和數(shù)據(jù),得到以下結(jié)論:
1.dynamic***使用會產(chǎn)生一定的性能損耗
2.無論是否***使用,使用次數(shù)達到一定量級,dynamic性能一定優(yōu)于Dictionary
3.一次運行中連續(xù)使用dynamic會顯著拉低平均性能損耗
考慮到傳遞變參可能出現(xiàn)多個參數(shù),以上測試不完全。
使用以下代碼進行第二階段實驗:
- public void InvokeDynamic()
- {
- var e = CallDynamic2(
- new { Value1 = 0, Value2 = 0L, Value3 = 0f, Value4 = 0.0, Value5 = "test" });
- int v1 = e.Value1;
- long v2 = e.Value2;
- float v3 = e.Value3;
- double v4 = e.Value4;
- string v5 = e.Value5;
- }
- public void InvokeDictionary()
- {
- var dict = new Dictionary<string, object>();
- dict["Value1"] = 0;
- dict["Value2"] = 0L;
- dict["Value3"] = 0f;
- dict["Value4"] = 0.0;
- dict["Value5"] = "test";
- dict = CallDictionary2(dict);
- int v1 = (int)dict["Value1"];
- long v2 = (long)dict["Value2"];
- float v3 = (float)dict["Value3"];
- double v4 = (double)dict["Value4"];
- string v5 = (string)dict["Value5"];
- }
- private dynamic CallDynamic2(dynamic test)
- {
- int v1 = test.Value1;
- long v2 = test.Value2;
- float v3 = test.Value3;
- double v4 = test.Value4;
- string v5 = test.Value5;
- v1++;
- v2++;
- v3++;
- v4++;
- v5 += "test";
- return new { Value1 = v1, Value2 = v2, Value3 = v3, Value4 = v4, Value5 = v5 };
- }
- private Dictionary<string, object> CallDictionary2(
- Dictionary<string, object> test)
- {
- int v1 = (int)test["Value1"];
- long v2 = (long)test["Value2"];
- float v3 = (float)test["Value3"];
- double v4 = (double)test["Value4"];
- string v5 = (string)test["Value5"];
- v1++;
- v2++;
- v3++;
- v4++;
- v5 += "test";
- var dict = new Dictionary<string, object>();
- dict["Value1"] = v1;
- dict["Value2"] = v2;
- dict["Value3"] = v3;
- dict["Value4"] = v4;
- dict["Value5"] = v5;
- return dict;
- }
結(jié)果數(shù)據(jù):
***決定選擇使用dynamic
有兄弟考慮可能Box損耗了性能導(dǎo)致Dictionary表現(xiàn)不佳,
專門做了第三階段實驗,對比dynamic和Dictionary<string,long>
具體數(shù)據(jù)不貼了,結(jié)果是dynamic在100000量級快一倍