Exact Time Measurement for Performance Testing

Exact time measurement for performance testing

A better way is to use the Stopwatch class:

using System.Diagnostics;
// ...

Stopwatch sw = new Stopwatch();

sw.Start();

// ...

sw.Stop();

Console.WriteLine("Elapsed={0}",sw.Elapsed);

How can I time a code segment for testing performance with Pythons timeit?

You can use time.time() or time.clock() before and after the block you want to time.

import time

t0 = time.time()
code_block
t1 = time.time()

total = t1-t0

This method is not as exact as timeit (it does not average several runs) but it is straightforward.

time.time() (in Windows and Linux) and time.clock() (in Linux) are not precise enough for fast functions (you get total = 0). In this case or if you want to average the time elapsed by several runs, you have to manually call the function multiple times (As I think you already do in you example code and timeit does automatically when you set its number argument)

import time

def myfast():
   code

n = 10000
t0 = time.time()
for i in range(n): myfast()
t1 = time.time()

total_n = t1-t0

In Windows, as Corey stated in the comment, time.clock() has much higher precision (microsecond instead of second) and is preferred over time.time().

Performance Testing: Flag when a UI/API test's runtime increases by x% (Selenium C#)

IMHO there are too many wrong things on too many levels with this request.

these tests track their own performance (and past performance) and raise a warning when its runtime increases by x% (5% or 10%, etc).

Performance metrics of functional UI/API test proves what, exactly!?

However, in case this still have to be implemented, I would suggest a simple approach - use StopWatch in before/after each C# Selenium test and store this in a central DB, which you can later query and flag in case of increase.

// generate test case id for later use
// create and start the instance of Stopwatch in your [SetUp] method
Stopwatch stopwatch = Stopwatch.StartNew(); 
// your test code here
// in your [TearDown] method
stopwatch.Stop();
// store this in the DB alongside TestCaseId
Console.WriteLine(stopwatch.ElapsedMilliseconds);  

Calculate the execution time of a method

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

---

UPDATE:

As pointed out by @series0ne in the comments section: If you want a real precise measurement of the execution of some code, you will have to use the performance counters that's built into the operating system. The following answer contains a nice overview.

How can I run my performance tests more than ten times?

In the latest Xcode (11.0+) you don't need swizzling to change iterations count. Use the following function:

func measure(options: XCTMeasureOptions, block: () -> Void)

This will allow you to specify XCTMeasureOptions which has iterationCount property.

Interesting note from docs:

A performance test runs its block iterationCount+1 times, ignoring the first iteration and recording metrics for the remaining iterations. The test ignores the first iteration to reduce measurement variance associated with “warming up” caches and other first-run behavior.

How to measure code performance in .NET?

The Stopwatch class, available since .NET 2.0, is the best way to go for this. It is a very high performance counter accurate to fractions of a millisecond.
Take a look at the MSDN documentation, which is pretty clear.

EDIT: As previously suggested, it is also advisable to run your code a number of times in order to get a reasonable average time.

---

Related Topics