[ulber]

Here's the issue on GitHub if you'd like to track it: https://github.com/Microsoft/BashOnWindows/issues/1671

benhills describes the cause:

For some context, I've looked at what causes this slowdown. For some reason stack has mapped an mind-bogglingly huge region of memory (I'm talking dozens of terabytes). When we fork we walk the entire address range to set up the new process's state. We have a design that should vastly speed this up, but we're approaching "pencils down" date for Creators Update.

[codebook]

Thanks for the info!. I will try again.

[hornetblack]

For some context: amd64 has 256TiB of address space. So 1 dozen is half a percent of what seems like a mind boggling amount of address space.