A PowerShell Function that uses asynchronous ping commands to quickly ping a fleet of target machines.

Invoke-FastPing

<#
    .SYNOPSIS
    Performs a series of asynchronous pings against the target hosts.

    .PARAMETER HostName
    A string array of target hosts to ping.

    .PARAMETER PingCount
    The number of pings to send against each host.
#>
function Invoke-FastPing
{
    [alias('FastPing', 'fping', 'fp')]
    param
    (
        [Parameter(ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)]
        [ValidateNotNullOrEmpty()]
        [Alias('Computer', 'ComputerName', 'Host')]
        [String[]] $HostName,

        [Int] $PingCount = 4
    )

    process
    {
        # Objects to hold items as we process pings
        $queue = [System.Collections.Queue]::new()
        $pingHash = @{}

        # Start an asynchronous ping against each computer
        foreach ($hn in $HostName)
        {
            if ($pingHash.Keys -notcontains $hn)
            {
                $pingHash.Add($hn, [System.Collections.ArrayList]::new())
            }

            for ($i = 0; $i -lt $PingCount; $i++)
            {
                $ping = [System.Net.Networkinformation.Ping]::new()
                $object = @{
                    Host = $hn
                    Ping = $ping
                    Async = $ping.SendPingAsync($hn)
                }
                $queue.Enqueue($object)
            }
        }

        # Process the asynchronous pings
        while ($queue.Count -gt 0)
        {
            $object = $queue.Dequeue()
            if ($object.Async.IsCompleted -eq $true)
            {
                $null = $pingHash[$object.Host].Add(@{
                    Host = $object.Host
                    RoundtripTime = $object.Async.Result.RoundtripTime
                    Status = $object.Async.Status
                })
            }
            else
            {
                $queue.Enqueue($object)
            }
        }

        # Using the ping results in pingHash, calculate the average RoundtripTime
        foreach ($key in $pingHash.Keys)
        {
            if (($pingHash.$key.Status | Select-Object -Unique) -eq 'RanToCompletion')
            {
                $online = $true
            }
            else
            {
                $online = $false
            }

            if ($online -eq $true)
            {
                $latency = [System.Collections.ArrayList]::new()
                foreach ($value in $pingHash.$key)
                {
                    if ($value.RoundtripTime)
                    {
                        $null = $latency.Add($value.RoundtripTime)
                    }
                }

                $average = $latency | Measure-Object -Average
                if ($average.Average)
                {
                    $roundtripAverage = [Math]::Round($average.Average, 0)
                }
                else
                {
                    $roundtripAverage = $null
                }
            }
            else
            {
                $roundtripAverage = $null
            }

            [PSCustomObject]@{
                ComputerName = $key
                RoundtripAverage = $roundtripAverage
                Online = $online
            }
        }

    } # End Process
}