When we have to calibrate the performance of a loop, method or block of code we quickly tend to throw in few datetime.now and calculate the time difference. This approach has some flaws and does not provide accurate results. One major reason is datetime.now has a very low resolution depending on the computer, a typical computer has a resolution of somewhere around 100 ticks per second.
Microsoft introduced the Stopwatch class to help developers get more accurate time stamp. Stopwatch is generally more precise then datetime.now and secondly it’s more lightweight, also it support object oriented design. So what does the stopwatch class do, It just stores the current time-stamp (via QueryPerformanceCounter) when you start it, and compare it to the time-stamp when you stop it, so between start and stop it does not use cpu cycles and so it does not effect the performance of your code. Stopwatch was designed specifically for accurate time measurements, so you can be sure it is optimized. Though it would be a good idea to remove any performance counters in a release build. It is also much more accurate than comparing successive values of datetime.now.
For everyday debugging use case we need a easy and clean code to calculate execution time, so lets create a re-usable class that can be easily used to measure performance of our code.
1:using System;
2:using System.Diagnostics;
3: 4:namespace Common.Helper
5: {6:publicclass StopWatchHelper
7: {8:publicstaticvoid CalculateTime(string stopWatchLabel, Action action)
9: {10: var internalStopWatch = new InternalStopWatch();
11: action();12: PrintToConsole(internalStopWatch.TimeDifference(), null, stopWatchLabel);
13: } 14: 15:publicstaticvoid CalculateTime(Action action)
16: {17: var internalStopWatch = new InternalStopWatch();
18: action();19: PrintToConsole(internalStopWatch.TimeDifference(), action.Method.Name, null,
20:new StackTrace(new StackFrame(1, true)));
21: } 22: 23:privatestaticvoid PrintToConsole(TimeSpan timeDifference, string methodName = null,
24:string stopWatchLabel = null, StackTrace st = null)
25: {26:if (string.IsNullOrEmpty(stopWatchLabel))
27: { 28: PrintDottedLine();29: Console.WriteLine(" Method : {0} ", methodName);
30: Console.WriteLine(" Time : {0} ", timeDifference);
31: Console.WriteLine(" Location: {0}", st);
32: PrintDottedLine(); 33: }34:else
35: { 36: PrintDottedLine();37: Console.WriteLine(" Label : {0} ", stopWatchLabel);
38: Console.WriteLine(" Time : {0} ", timeDifference);
39: PrintDottedLine(); 40: } 41: } 42: 43:privatestaticvoid PrintDottedLine()
44: {45: Console.WriteLine("-------------------------------------------------\n");
46: } 47: 48: } 49: 50:internalclass InternalStopWatch
51: {52:privatereadonly Stopwatch stopwatch;
53: 54:public InternalStopWatch()
55: {56: stopwatch = new Stopwatch();
57: stopwatch.Start(); 58: } 59: 60:public TimeSpan TimeDifference()
61: { 62: stopwatch.Stop();63:return stopwatch.Elapsed;
64: } 65: 66: } 67: 68: }Code for the main console application
1:using System;
2:using System.Collections.Generic;
3:using Common.Helper;
4: 5:namespace StopWatchHelperConsole
6: {7:internalclass Program
8: {9:privatestaticvoid Main(string[] args)
10: {11://If not release mode then exit the application
12:if (!CheckIfReleaseMode()) return;
13: 14://Single line statment
15: var list = CreateNewList(); 16: StopWatchHelper.CalculateTime(list.Sort); 17: 18://Use Lambda
19: list = CreateNewList(); 20: StopWatchHelper.CalculateTime(() => { list.Sort(); }); 21: 22://User a label to indicate the location
23: list = CreateNewList();24: StopWatchHelper.CalculateTime("StopWatch for List", () =>
25: { 26: list.Sort(); 27: list.Sort(); 28: }); 29: 30: Console.Read(); 31: } 32: 33:privatestatic List CreateNewList()
34: {35: var list = new List();
36:constint size = 10000;
37: var random = new Random();
38:for (int i = 0; i < size; ++i)
39: list.Add(random.Next());40:return list;
41: } 42: 43:privatestaticbool CheckIfReleaseMode()
44: {45:#if DEBUG
46: Console.WriteLine("Performance test should be done in Relase Mode");
47: Console.Read();48:returnfalse;
49:#else
50:returntrue;
51:#endif
52: } 53: 54: }Output on the console screen
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| Console Output |