Thread Job Performance in PowerShell

# Thread job performance
#
# Thread jobs are faster and lighter weight than other types of jobs.
# But they still have overhead that can be large when compared to work the job is doing.
#
# Thread jobs provide the best performance when the work they perform is
# greater than the overhead of the session used to run the job. There are two cases for that meet this criteria.
#
# 1. Work is compute intensive - Running a script on multiple thread jobs can take advantage of multiple processor cores and complete faster.
# 2. Work consists of significant waiting - A script that spends time waiting for I/O or remote call results. Running in parallel usually completes quicker than if run sequentially.
#
# Article: [Thread job performance](https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_thread_jobs?view=powershell-7.4#thread-job-performance)
#

# Measure-Command {
#     $logs = $logNames | ForEach-Object {
#         Start-ThreadJob {
#             Get-WinEvent -LogName $using:_ -MaxEvents 5000 2>$null
#         } -ThrottleLimit 10
#     } | Wait-Job | Receive-Job
# }
# TotalMilliseconds : 115994.3 (1 minute 56 seconds)
# $logs.Count
# 50000

$items = @()
$itemLimit = 10
$throttleLimit = 10
$sleepSeconds = 1

# Build the list of items to iterate over, in this case we use server<index>.
for ($i = 0; $i -lt $itemLimit; $i++)
{
    $items += ('server{0}' -f $i)
}

function RunThreadedJobs()
{
    Write-Host "-------------------------`nRunThreadedJobs`n-------------------------" -ForegroundColor Cyan

    $sw = [Diagnostics.Stopwatch]::StartNew()

    $results = $items | ForEach-Object {
        Start-ThreadJob {
            Write-Output -InputObject $using:_ # server<index>
            Start-Sleep -Seconds $using:sleepSeconds
        } -ThrottleLimit $throttleLimit
    } | Wait-Job | Receive-Job

    $sw.Stop()

    $results

    $outputObj = [PSCustomObject]@{
        TotalSeconds = $sw.Elapsed.TotalSeconds
        TotalResults = $results.Count
        TotalItems = $items.Count
        ItemLimit = $itemLimit
        ThrottleLimit = $throttleLimit
        SleepSeconds = $sleepSeconds
    }

    $outputObj | Format-List
    # TotalSeconds  : 2.1986528
    # TotalResults  : 10
    # TotalItems    : 10
    # ItemLimit     : 10
    # ThrottleLimit : 10
    # SleepSeconds  : 1
}

function RunSync()
{
    Write-Host "-------------------------`nRunSync`n-------------------------" -ForegroundColor Cyan

    $sw = [Diagnostics.Stopwatch]::StartNew()

    $results = $items | ForEach-Object {
        Write-Output -InputObject $_ # server<number>
        Start-Sleep -Seconds $sleepSeconds
    }

    $sw.Stop()

    $results

    $outputObj = [PSCustomObject]@{
        TotalSeconds = $sw.Elapsed.TotalSeconds
        TotalResults = $results.Count
        TotalItems = $items.Count
        ItemLimit = $itemLimit
        ThrottleLimit = 'N/A'
        SleepSeconds = $sleepSeconds
    }

    $outputObj | Format-List
    # TotalSeconds  : 10.0176677
    # TotalResults  : 10
    # TotalItems    : 10
    # ItemLimit     : 10
    # ThrottleLimit : N/A
    # SleepSeconds  : 1
}

RunThreadedJobs
RunSync