Powershell: Performance Issue with foreach - paralllel

[Schwanowski]

Hi guys

the attached test runs on my machine (Powershell V7) astonishingly 30 seconds.

Can this be true? It has only 10k records and I dont get the performance issue?

Can you please clarify the issue?

Thanks,

Alex

tmp.txt

Steps to reproduce

    $myTest = Get-Content 'tmp.txt' | ConvertFrom-Json | Select-Object 'InputObject'
Measure-Command {
    $myTest | ForEach-Object -parallel {}
}

Expected behavior

This shouldnt take 30 seconds imho

Environment data

$PSVersionTable.PSVersion


Major  Minor  Patch  PreReleaseLabel BuildLabel
-----  -----  -----  --------------- ----------
7      0      0

[iSazonov]

@Schwanowski In 7.0 new runspaces is created for every input object. It is really slow.
You can try latest 7.1 preview nightly build where some optimizations was added.

[vexx32]

Additionally, if the overall processing required for each runspace is small, you will have better results in both versions if you batch the inputs for processing.

[Schwanowski]

Thanks, we can leave this for the moment. I will try this again when 7.1 is out