Is DateTime.Now the best way to measure a function's performance? [closed]

Answer 1

This is the correct way:

using System;
using System.Diagnostics;

class Program
{
    public static void Main()
    {
        Stopwatch stopWatch = Stopwatch.StartNew();

            // some other code

        stopWatch.Stop();

        // this not correct to get full timer resolution
        Console.WriteLine("{0} ms", stopWatch.ElapsedMilliseconds);

        // Correct way to get accurate high precision timing
        Console.WriteLine("{0} ms", stopWatch.Elapsed.TotalMilliseconds);
    }
}

For more information go through Use Stopwatch instead of DataTime for getting accurate performance counter.

Answer 2

I just found a post in Vance Morrison's blog about a CodeTimer class he wrote that makes using StopWatch easier and does some neat stuff on the side.

Answer 3

The stopwatch functionality would be better (higher precision). I'd also recommend just downloading one of the popular profilers, though (DotTrace and ANTS are the ones I've used the most... the free trial for DotTrace is fully functional and doesn't nag like some of the others).

Answer 4

Ditto Stopwatch, it is way better.

Regarding performance measuring you should also check whether your "// Some Execution Process" is a very short process.

Also bear in mind that the first run of your "// Some Execution Process" might be way slower than subsequent runs.

I typically test a method by running it 1000 times or 1000000 times in a loop and I get much more accurate data than running it once.

Answer 5

This is not professional enough:

Stopwatch sw = Stopwatch.StartNew();
PerformWork();
sw.Stop();

Console.WriteLine("Time taken: {0}ms", sw.Elapsed.TotalMilliseconds);

A more reliable version is:

PerformWork();

int repeat = 1000;

Stopwatch sw = Stopwatch.StartNew();
for (int i = 0; i < repeat; i++)
{
   PerformWork();
}

sw.Stop();

Console.WriteLine("Time taken: {0}ms", sw.Elapsed.TotalMilliseconds / repeat);

In my real code, I will add GC.Collect call to change managed heap to a known state, and add Sleep call so that different intervals of code can be easily separated in ETW profile.

Answer 6

I've done very little of this sort of performance checking (I tend to just think "this is slow, make it faster") so I have pretty much always gone with this.

A google does reveal a lot of resources/articles for performance checking.

Many mention using pinvoke to get performance information. A lot of the materials I study only really mention using perfmon..

Edit:

Seen the talks of StopWatch.. Nice! I have learned something :)

This looks like a good article