PowerShell How-To

Using a Stopwatch In PowerShell

Monitoring the speed at which code is executed will give a window into avenues to improve it for efficiency.

Ever wonder how long a piece of PowerShell code takes to execute? Maybe you've got a script that occasionally gets hung up on some process, and you'd like a way to terminate the script if it takes too long. If so, you're going to love the System.Diagnostics.Stopwatch .NET class available in PowerShell. Using a Stopwatch object allows you to precisely measure a start and stop time which opens up all kinds of opportunities in a PowerShell script.

To use the Stopwatch object, let's first create an object using a static method called StartNew().


$stopwatch =  [system.diagnostics.stopwatch]::StartNew()

Once the object has been created, it is continually running in the background. Every time the value of $stopwatch is checked, you'll see a different time down to the microsecond level.


PS C:\> $stopwatch =  [system.diagnostics.stopwatch]::StartNew()
PS C:\> $stopwatch

IsRunning Elapsed          ElapsedMilliseconds ElapsedTicks
--------- -------          ------------------- ------------
True 00:00:02.2956772                2299     22990551

PS C:\> $stopwatch

IsRunning Elapsed          ElapsedMilliseconds ElapsedTicks
--------- -------          ------------------- ------------
True 00:00:04.0694321                4069     40694669

PS C:\> $stopwatch

IsRunning Elapsed          ElapsedMilliseconds ElapsedTicks
--------- -------          ------------------- ------------
True 00:00:05.1999316                5199     51999528
We can also use the Elapsed property to see all of the time metrics easier.
PS C:\> $stopwatch.Elapsed

Days              : 0
Hours             : 0
Minutes           : 1
Seconds           : 23
Milliseconds      : 795
Ticks             : 837958187
TotalDays         : 0.000969859012731481
TotalHours        : 0.0232766163055556
TotalMinutes      : 1.39659697833333
TotalSeconds      : 83.7958187
TotalMilliseconds : 83795.8187

We can check to see if the stopwatch is running or not by using the IsRunning property and finally stop the stopwatch by using the Stop() method.

PS C:\> $stopwatch.IsRunning
PS C:\> $stopwatch.Stop()
PS C:\> $stopwatch.IsRunning

How the this method be used in a real-world situation? One great use of using the stopwatch is by creating a timeout. Let's say you've got a task that sometimes gets hung up and you want to ensure the entire script doesn't stop if this happens. We can use the stopwatch by including it in a while loop. Below is an example of checking the total seconds the stopwatch has been running and then executing some code. To prevent from attempting to execute the code every microsecond or less I've added a sleep cmdlet in there so that it will only check every second.

while ($timer.Elapsed.TotalSeconds -lt 10) {
## Do some stuff here

## Wait a specific interval
Start-Sleep -Seconds 1

## Check the time
$totalSecs = [math]::Round($timer.Elapsed.TotalSeconds,0)
Write-Verbose -Message "Still waiting for action to complete after [$totalSecs] seconds..."

This example ensures that the code inside of the while loop does not execute for longer than ten seconds. Using a timeout is a great way to use this useful .NET object. What other applications do you see that would come in handy by using the stopwatch?

About the Author

Adam Bertram is a 20-year veteran of IT. He's an automation engineer, blogger, consultant, freelance writer, Pluralsight course author and content marketing advisor to multiple technology companies. Adam also founded the popular TechSnips e-learning platform. He mainly focuses on DevOps, system management and automation technologies, as well as various cloud platforms mostly in the Microsoft space. He is a Microsoft Cloud and Datacenter Management MVP who absorbs knowledge from the IT field and explains it in an easy-to-understand fashion. Catch up on Adam's articles at adamtheautomator.com, connect on LinkedIn or follow him on Twitter at @adbertram or the TechSnips Twitter account @techsnips_io.

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