Cross function boundary perf

Cross function boundary

# Quickly measuring if it is better to call function in foreach loop or gerate the array and pass it in the function once
# and then iterate over the array inside of the function
"`n"
# cross function boundary 10,000 times
$script:b = 0
function a ($a) { $script:b += $a }
$sw = [Diagnostics.StopWatch]::StartNew()
foreach ($_ in 1..10000) {
    a 1
}
"10k function:`t$script:b iter, $($sw.ElapsedMilliseconds) ms"


# cross function boundary once with array of 10,000 items
$script:b = 0
function a ($a) {
    foreach ($i in $a) {
        $script:b += $i
    }
}

$sw = [Diagnostics.StopWatch]::StartNew()
$a = foreach ($_ in 1..10000) {
    1
}

a $a
"1 function:`t$script:b iter, $($sw.ElapsedMilliseconds) ms"


# cross cmdlet boundary 10,000 times
$script:b = 0
function a {
    [CmdletBinding()]
    param ($a) 
    $script:b += $a 
}
$sw = [Diagnostics.StopWatch]::StartNew()
foreach ($_ in 1..10000) {
    a 1
}
"10k cmdlet:`t$script:b iter, $($sw.ElapsedMilliseconds) ms"


# cross cmdlet boundary once with array of 10,000 items
$script:b = 0
function a {
    [CmdletBinding()]
    param ($a) 

    foreach ($i in $a) {
        $script:b += $i
    }
}

$sw = [Diagnostics.StopWatch]::StartNew()
$a = foreach ($_ in 1..10000) {
    1
}

a $a
"1 cmdlet:`t$script:b iter, $($sw.ElapsedMilliseconds) ms"


# cross sb boundary 10,000 times
$script:b = 0
$sb = { param ($a) $script:b += $a } 
$sw = [Diagnostics.StopWatch]::StartNew()
foreach ($_ in 1..10000) {
    & $sb 1
}
"10k sb:`t`t$script:b iter, $($sw.ElapsedMilliseconds) ms"

# cross sb boundary once with array of 10,000 items
$script:b = 0
$sb = { 
    param($a)
    foreach ($i in $a) {
        $script:b += $i
    }
}

$sw = [Diagnostics.StopWatch]::StartNew()
$a = foreach ($_ in 1..10000) {
    1
}

& $sb $a
"1 sb:`t`t$script:b iter, $($sw.ElapsedMilliseconds) ms"




# cross sb boundary with hashtable lookup 10k times
$script:b = 0
function a { 
    param($a)
    foreach ($i in $a) {
        $script:b += $i
    }
}

$hash = Get-Command -CommandType function | Select -First 400 | foreach { $hash = @{}} { $hash.($_.Name) = $_} { $hash }

$sw = [Diagnostics.StopWatch]::StartNew()
$a = foreach ($_ in 1..10000) {
    & $hash.a 1
}

"10k hash:`t$script:b iter, $($sw.ElapsedMilliseconds) ms"

results.txt

10k function:   10000 iter, 312 ms
1 function:     10000 iter, 8 ms
10k cmdlet:     10000 iter, 321 ms
1 cmdlet:       10000 iter, 10 ms
10k sb:         10000 iter, 200 ms
1 sb:           10000 iter, 13 ms
10k hash:               10000 iter, 213 ms
PS C:\Projects\pester>

10k function:   10000 iter, 277 ms
1 function:     10000 iter, 9 ms
10k cmdlet:     10000 iter, 318 ms
1 cmdlet:       10000 iter, 8 ms
10k sb:         10000 iter, 198 ms
1 sb:           10000 iter, 12 ms
10k hash:       10000 iter, 219 ms
PS C:\Projects\pester>

10k function:   10000 iter, 313 ms
1 function:     10000 iter, 9 ms
10k cmdlet:     10000 iter, 336 ms
1 cmdlet:       10000 iter, 9 ms
10k sb:         10000 iter, 230 ms
1 sb:           10000 iter, 12 ms
10k hash:       10000 iter, 213 ms
PS C:\Projects\pester>

10k function:   10000 iter, 311 ms
1 function:     10000 iter, 8 ms
10k cmdlet:     10000 iter, 344 ms
1 cmdlet:       10000 iter, 9 ms
10k sb:         10000 iter, 221 ms
1 sb:           10000 iter, 10 ms
10k hash:       10000 iter, 217 ms