Measure'm all

One of my scripting mottos is to always aspire to script with less steps and at the same time in the fastest way. Basically, you can get from point A to point B in various ways, but in the end, you need to decide which path to choose and how efficient it is.

Back in the VBScript days (seems like a very a long time ago), measuring the time that took your scripts/commands to execute was involved in writing a custom procedure, capturing the date/time before and after the action, and using DATEDIFF function to calculate the difference. Using PS> You can still use the "old" method.

This sample assigns the starting time to $s, executes the main command ($t), and then uses the New-TimeSpan cmdlet to calculate the time difference.

 

$s=(get-date)
$t=Get-ChildItem "C:\Documents and Settings" -filter *.txt -recurse
New-TimeSpan -start $s

Days : 0
Hours : 0
Minutes : 0
Seconds : 0
Milliseconds : 453
Ticks : 4531250
TotalDays : 5.24450231481481E-06
TotalHours : 0.000125868055555556
TotalMinutes : 0.00755208333333333
TotalSeconds : 0.453125
TotalMilliseconds : 453.125

 

Now, there's no need to write the whole procedure.
There's a built-in cmdlet called Measure-Command specially created for this kind of task, only it is much simpler and shorter:

Measure-Command {Get-ChildItem "C:\Documents and Settings" -filter *.txt -recurse}

Days : 0
Hours : 0
Minutes : 0
Seconds : 0
Milliseconds : 452
Ticks : 4525956
TotalDays : 5.238375E-06
TotalHours : 0.000125721
TotalMinutes : 0.00754326
TotalSeconds : 0.4525956
TotalMilliseconds : 452.5956

 

You can even measure a few lines of code:

Measure-Command {Get-ChildItem "C:\Documents and Settings" -filter *.txt -recurse ;Get-Process; Get-Service }

If you need to test a more complex command structure, consider saving the commands into a .ps1 file and then execute it via Measure-Command:

Measure-Command {& c:\measurec.ps1}

Days : 0
Hours : 0
Minutes : 0
Seconds : 0
Milliseconds : 433
Ticks : 4331861
TotalDays : 5.01372800925926E-06
TotalHours : 0.000120329472222222
TotalMinutes : 0.00721976833333333
TotalSeconds : 0.4331861
TotalMilliseconds : 433.1861

That way you can test various scripts/commands that execute procedures using different scripting methods and decide, based on the results, which one to implement. Here is a little teaser. Can you tell which for-loop is faster?

Counting from 1 to 1000?
for($i=0;$i -le 1000;$i++) {$d+=($i*1000)/2}

-or- from 1000 to 1?

for($i=1000;$i -ge 0;$i--) {$d+=($i*1000)/2}

 

Now you can measure it up, for-loops vs. while-loops and so on :-)

 

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