Measuring code execution time in this code

Question

I want to know how much time a procedure/function/order takes to finish, for testing purposes.

This is what I did, but my method is wrong, because if the difference of seconds is 0, it can't return the elapsed milliseconds:

Notice the sleep value is 500 ms, so elapsed seconds is 0, and then it can't return milliseconds.

    Dim Execution_Start As System.DateTime = System.DateTime.Now
    Threading.Thread.Sleep(500)

    Dim Execution_End As System.DateTime = System.DateTime.Now
    MsgBox(String.Format("H:{0} M:{1} S:{2} MS:{3}", _
    DateDiff(DateInterval.Hour, Execution_Start, Execution_End), _
    DateDiff(DateInterval.Minute, Execution_Start, Execution_End), _
    DateDiff(DateInterval.Second, Execution_Start, Execution_End), _
    DateDiff(DateInterval.Second, Execution_Start, Execution_End) * 60))

Is there a better way to do this? Maybe with a TimeSpan?

The solution:

Dim Execution_Start As New Stopwatch
Execution_Start.Start()

Threading.Thread.Sleep(500)

MessageBox.Show("H:" & Execution_Start.Elapsed.Hours & vbNewLine & _
       "M:" & Execution_Start.Elapsed.Minutes & vbNewLine & _
       "S:" & Execution_Start.Elapsed.Seconds & vbNewLine & _
       "MS:" & Execution_Start.Elapsed.Milliseconds & vbNewLine, _
       "Code execution time", MessageBoxButtons.OK, MessageBoxIcon.Information)

@Soner If I tagged it with C# is because C# code is welcome for me. — ElektroStudios
– ElektroStudios, Commented May 4, 2013 at 16:14
Besides the obvious reasons to use a stopwatch, you should never do any math with DateTime.Now due to Daylight Savings and Time Zone issues. Please read my blog post on this very subject — Matt Johnson-Pint
– Matt Johnson-Pint, Commented May 6, 2013 at 0:18
Possible duplicate of Is DateTime.Now the best way to measure a function's performance? — Michael Freidgeim
– Michael Freidgeim, Commented Jun 19, 2017 at 3:41
Possible duplicate of Calculate the execution time of a method — StayOnTarget
– StayOnTarget, Commented Mar 27, 2019 at 19:53

juliand665 · Accepted Answer · 2021-08-17 08:25:38Z

296

A better way would be to use Stopwatch, instead of DateTime differences.

Stopwatch Class - Microsoft Docs

Provides a set of methods and properties that you can use to accurately measure elapsed time.

// create and start a Stopwatch instance
Stopwatch stopwatch = Stopwatch.StartNew(); 

// replace with your sample code:
System.Threading.Thread.Sleep(500);

stopwatch.Stop();
Console.WriteLine(stopwatch.ElapsedMilliseconds);

edited Aug 17, 2021 at 8:25

juliand665

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answered May 4, 2013 at 16:00

Habib

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4 Comments

Chai Over a year ago

Please refer github.com/chai-deshpande/LogExec (a NUGET package is also available nuget.org/packages/LogExec). This does the exact same things that @soner-gonul mentioned - but, the usage is clutter free and hides all the boilerplate code. Very helpful when you want to use it very frequently. It also uses Common.Logging so that you can integrate with your preferred logging provider.

Md Sifatul Islam Over a year ago

@Habib can you please help me to understand why is Thread.sleep(500) is necessary? Cant i do it skipping sleep, would that make it less efficient?

Habib Over a year ago

@Md.SifatulIslam, there is no need to use Thread.Sleep, it just there as a sample code to show delay.... in fact you should avoid using Thread.Sleep anywhere in your code

mcu Over a year ago

But this does not measure the process time, so the result is affected by other processes running on the system.

Pang · Accepted Answer · 2022-06-07 06:30:40Z

73

Stopwatch measures time elapsed.

// Create new stopwatch
Stopwatch stopwatch = new Stopwatch();

// Begin timing
stopwatch.Start();

Threading.Thread.Sleep(500)

// Stop timing
stopwatch.Stop();

Console.WriteLine("Time elapsed: {0}", stopwatch.Elapsed);

Here is a DEMO.

edited Jun 7, 2022 at 6:30

Pang

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answered May 4, 2013 at 16:08

Soner Gönül

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4 Comments

vaheeds Over a year ago

can it used for execution time of each line of code? e.g: bindingSource.datasource = db.table; // how much it takes long?

Soner Gönül Over a year ago

@vaheeds Sure. Just start this Stopwatch on top of your each line and stop it after your each line. Remember, you need to use also Stopwatch.Reset on after every single line to calculate. Based on your line; take a look ideone.com/DjR6ba

Doruk Over a year ago

i did a little trick on it to get the miliseconds out of picture. this way watch.Elapsed.ToString().Split('.')[0]

Soner Gönül Over a year ago

@Doruk Yeah, you can do that or you can use Custom Timespan Format Strings like stopwatch.Elapsed.ToString(@"d\.hh\:mm\:ss") which seems a cleaner way to me.

Alex Erygin · Accepted Answer · 2019-10-28 06:11:29Z

63

You can use this Stopwatch wrapper:

public class Benchmark : IDisposable 
{
    private readonly Stopwatch timer = new Stopwatch();
    private readonly string benchmarkName;

    public Benchmark(string benchmarkName)
    {
        this.benchmarkName = benchmarkName;
        timer.Start();
    }

    public void Dispose() 
    {
        timer.Stop();
        Console.WriteLine($"{benchmarkName} {timer.Elapsed}");
    }
}

Usage:

using (var bench = new Benchmark($"Insert {n} records:"))
{
    ... your code here
}

Output:

Insert 10 records: 00:00:00.0617594

For advanced scenarios, you can use BenchmarkDotNet or Benchmark.It or NBench

edited Oct 28, 2019 at 6:11

answered Jun 5, 2016 at 9:08

Alex Erygin

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Comments

Marcell · Accepted Answer · 2014-10-01 07:15:50Z

16

If you use the Stopwatch class, you can use the .StartNew() method to reset the watch to 0. So you don't have to call .Reset() followed by .Start(). Might come in handy.

answered Oct 1, 2014 at 7:15

Marcell

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Comments

Shailesh Prajapati · Accepted Answer · 2018-04-16 11:42:47Z

5

If you are looking for the amount of time that the associated thread has spent running code inside the application.
You can use ProcessThread.UserProcessorTime Property which you can get under System.Diagnostics namespace.

TimeSpan startTime= Process.GetCurrentProcess().Threads[i].UserProcessorTime; // i being your thread number, make it 0 for main
//Write your function here
TimeSpan duration = Process.GetCurrentProcess().Threads[i].UserProcessorTime.Subtract(startTime);

Console.WriteLine($"Time caluclated by CurrentProcess method: {duration.TotalSeconds}"); // This syntax works only with C# 6.0 and above

Note: If you are using multi threads, you can calculate the time of each thread individually and sum it up for calculating the total duration.

edited Apr 16, 2018 at 11:42

answered Apr 16, 2018 at 11:25

Shailesh Prajapati

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Comments

Pang · Accepted Answer · 2020-11-10 00:00:29Z

5

Stopwatch is designed for this purpose and is one of the best way to measure execution time in .NET.

var watch = System.Diagnostics.Stopwatch.StartNew();
/* the code that you want to measure comes here */
watch.Stop();
var elapsedMs = watch.ElapsedMilliseconds;

Do not use DateTimes to measure execution time in .NET.

edited Nov 10, 2020 at 0:00

Pang

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answered Mar 24, 2017 at 9:55

Sam

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Comments

Pang · Accepted Answer · 2020-11-09 23:59:38Z

3

Example for how one might use the Stopwatch class in VB.NET.

Dim Stopwatch As New Stopwatch

Stopwatch.Start()
            ''// Test Code
Stopwatch.Stop()
Console.WriteLine(Stopwatch.Elapsed.ToString)

Stopwatch.Restart()            
           ''// Test Again

Stopwatch.Stop()
Console.WriteLine(Stopwatch.Elapsed.ToString)

edited Nov 9, 2020 at 23:59

Pang

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answered Jan 29, 2020 at 8:39

Praxiom

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