When using & { process { $_ }} instead of Foreach-Object/Where-Object, there is a huge performance gain, apparently caused by using a simple function instead of an advanced function. Parameter binding is no issue for these cmdlets in the vast majority of use cases as users typically only use $_ in their payload scriptblocks, and thus internally switching to a simple function w/o cmdletbinding might improve the speed without having to reinvent the entire cmdlet.

I have an open issue #9941 for Where-Object. @daxian-dbw is taking care of it. Maybe those two can be worked together? Seems similar to me?

I guess there is 2 places for perf consideration:

• Bindings. If source collection is strong typed collection we could bind only once. For common case source collection may contains free-typed objects and we have to do binding for every object.
• Compilation. Perhaps we could compile to something more faster. Ex., for Where-Object a filter function is more faster than scriptblock, maybe a delegate is better. Although maybe this is again binding.

@lzybkr @daxian-dbw could the suggestion from @TobiasPSP be considered for 7.1? In his blog he shows many alternative approaches to speed up pwsh that should be unnecessary due to optimizations in the core.

@mi-hol Please check out the issue #10982. There is tons of discussion there.

This pull request has been automatically marked as Review Needed because it has been there has not been any activity for 7 days.
Mainainer, Please provide feedback and/or mark it as Waiting on Author

This pull request has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 15 days. It will be closed if no further activity occurs within 10 days of this comment.

Why did this PR get marked as 'Waiting on Author' when there wasn't any maintainer feedback that I can see?

EDIT: Oops, nevermind. Didn't notice daxian-dbw was part of the PowerShell team.