Most of the time while developing PowerShell scripts we don’t need to worry about performance, or execution time. After all, scripts were made to run automation in the background. However, as your scripts become more sophisticated, and you need to work with complex data or big data sizes, performance becomes something to keep in mind. Measuring a script execution time is the first step towards script optimization.<\/p>\n
PowerShell has a built-in cmdlet called Besides the two parameters, objects in the pipeline are also passed to the script block. Using the pipeline or the InputObject<\/strong> parameter.<\/p>\n To overcome this, you can use the invocation operator It’s also worth remember that if your script block modifies system resources, files, databases or any other static data, the object gets modified.<\/p>\n As a cool exercise, try figuring out why the output from We know that scripts executed with If you are serious about the performance variable, and want to keep the script block as clean as possible, we could elaborate our own function, and shape the output as we want.<\/p>\n The Note that there is overhead when using the InputObject<\/strong> parameter, meaning there is a difference in the overall execution time.<\/p>\n I hope you, like me, learned something new today, and had fun along the way.<\/p>\n Until a next time, happy scripting!<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" This post shows how to measure script execution time in PowerShell<\/p>\n","protected":false},"author":62334,"featured_media":77,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[13,2],"tags":[83,91,90,3],"class_list":["post-1007","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-powershell","category-powershell-community","tag-automation","tag-measure-command","tag-performance","tag-powershell"],"acf":[],"blog_post_summary":" This post shows how to measure script execution time in PowerShell<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/posts\/1007","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/users\/62334"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/comments?post=1007"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/posts\/1007\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/media\/77"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/media?parent=1007"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/categories?post=1007"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell-community\/wp-json\/wp\/v2\/tags?post=1007"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Measure-Command<\/code>, which measures the execution time of other cmdlets, or script blocks. It has two parameters:<\/p>\n\n
$_<\/code> or $PSItem<\/code> to access them.<\/li>\n<\/ul>\nMeasure-Command<\/code> returns an object of type System.TimeSpan<\/code>, giving us more flexibility on how to work with the result.<\/p>\nMeasure-Command { foreach ($number in 1..1000) { <# Do work #> } }<\/code><\/pre>\nDays : 0\nHours : 0\nMinutes : 0\nSeconds : 0\nMilliseconds : 8\nTicks : 85034\nTotalDays : 9.84189814814815E-08\nTotalHours : 2.36205555555556E-06\nTotalMinutes : 0.000141723333333333\nTotalSeconds : 0.0085034\nTotalMilliseconds : 8.5034<\/code><\/pre>\n1..1000 |\n Measure-Command -Expression { foreach ($number in $_) { <# Do work #> } } |\n Select-Object TotalMilliseconds<\/code><\/pre>\nTotalMilliseconds\n-----------------\n 10.60<\/code><\/pre>\nMeasure-Command -InputObject (1..1000) -Expression { $_ | % { <# Do work #> } } |\n Select-Object TotalMilliseconds<\/code><\/pre>\nTotalMilliseconds\n-----------------\n 19.98<\/code><\/pre>\nScope and Object Modification<\/h2>\n
Measure-Command<\/code> runs the script block in the current scope, meaning variables in the current scope gets modified if referenced in the script block.<\/p>\n$studyVariable = 0\nMeasure-Command { 1..10 | % { $studyVariable += 1 } }\nWrite-Host \"Current variable value: $studyVariable.\"<\/code><\/pre>\nDays : 0\nHours : 0\nMinutes : 0\nSeconds : 0\nMilliseconds : 15\nTicks : 155838\nTotalDays : 1.80368055555556E-07\nTotalHours : 4.32883333333333E-06\nTotalMinutes : 0.00025973\nTotalSeconds : 0.0155838\nTotalMilliseconds : 15.5838\n\nCurrent variable value: 10.<\/code><\/pre>\n&<\/code> and enclose the script block in {}<\/code>, to execute in a separate context.<\/p>\n$studyVariable = 0\nMeasure-Command { & { 1..10 | % { $studyVariable += 1 } } }\nWrite-Host \"Current variable value: $studyVariable.\"<\/code><\/pre>\nDays : 0\nHours : 0\nMinutes : 0\nSeconds : 0\nMilliseconds : 8\nTicks : 86542\nTotalDays : 1.00164351851852E-07\nTotalHours : 2.40394444444444E-06\nTotalMinutes : 0.000144236666666667\nTotalSeconds : 0.0086542\nTotalMilliseconds : 8.6542\n\nCurrent variable value: 0.<\/code><\/pre>\n$scriptBlock = {\n if (!(Test-Path -Path C:\\SuperCoolFolder)) {\n New-Item -Path C:\\ -Name SuperCoolFolder -ItemType Directory\n }\n}\n\nMeasure-Command -Expression { & $scriptBlock }\nGet-ChildItem C:\\ -Filter SuperCoolFolder | Select-Object FullName<\/code><\/pre>\nDays : 0\nHours : 0\nMinutes : 0\nSeconds : 0\nMilliseconds : 11\nTicks : 118978\nTotalDays : 1.37706018518519E-07\nTotalHours : 3.30494444444444E-06\nTotalMinutes : 0.000198296666666667\nTotalSeconds : 0.0118978\nTotalMilliseconds : 11.8978\n\nFullName : C:\\SuperCoolFolder<\/code><\/pre>\nNew-Item<\/code> didn’t show up.<\/p>\nOutput and Alternatives<\/h2>\n
Measure-Command<\/code> returns a System.TimeSpan<\/code> object, but not the result from the script. If your study also includes the result, there are two ways you can go about it.<\/p>\nSaving the output in a variable<\/h3>\n
Measure-Object<\/code> runs in the current scope. So we could assign the result to a variable, and work with it.<\/p>\n$range = 1..100\n$evenCount = 0\n$scriptBlock = {\n foreach ($number in $range) {\n if ($number % 2 -eq 0) {\n $evenCount++\n }\n }\n}\n\nMeasure-Command -InputObject (1..100) -Expression $scriptBlock |\n Format-List TotalMilliseconds\nWrite-Host \"The count of even numbers in 1..100 is $evenCount.\"<\/code><\/pre>\nTotalMilliseconds : 1.3838\n\nThe count of even numbers in 1..100 is 50.<\/code><\/pre>\nCustom Function<\/h3>\n
Measure-Command<\/code> Cmdlet uses an object called System.Diagnostics.Stopwatch<\/code>. It works like a real stopwatch, and we control it using its methods, like Start()<\/code>, Stop()<\/code>, etc. All we need to do is start it before executing our script block, stop it after execution finishes, and collect the result from the Elapsed<\/strong> property.<\/p>\nfunction Measure-CommandEx {\n\n [CmdletBinding()]\n param (\n [Parameter(Mandatory, Position = 0)]\n [scriptblock]$Expression,\n\n [Parameter(ValueFromPipeline)]\n [psobject[]]$InputObject\n )\n\n Begin {\n $stopWatch = New-Object -TypeName 'System.Diagnostics.Stopwatch'\n\n <#\n We need to define result as a list because the way objects\n are passed to the pipeline. If you pass a collection of objects,\n the pipeline sends them one by one, and the result\n is always overridden by the last item.\n #>\n [System.Collections.Generic.List[PSObject]]$result = @()\n }\n\n Process {\n if ($InputObject) {\n\n # Starting the stopwatch.\n $stopWatch.Start()\n\n # Creating the '$_' variable.\n $dollarUn = New-Object -TypeName psvariable -ArgumentList @('_', $InputObject)\n\n <#\n Overload is:\n InvokeWithContext(\n Dictionary<string, scriptblock> functionsToDefine,\n List<psvariable> variablesToDefine,\n object[] args\n )\n #>\n $result.AddRange($Expression.InvokeWithContext($null, $dollarUn, $null))\n\n $stopWatch.Stop()\n }\n else {\n $stopWatch.Start()\n $result.AddRange($Expression.InvokeReturnAsIs())\n $stopWatch.Stop()\n }\n }\n\n End {\n return [PSCustomObject]@{\n ElapsedTimespan = $stopWatch.Elapsed\n Result = $result\n }\n }\n}<\/code><\/pre>\nConclusion<\/h2>\n
Links<\/h2>\n
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