Comment by darrenf

> parallel: Warning: Finding the maximal command line length. This may take up to 1 minute.

> So I wait a few seconds [snip]

This warning is only ever printed if running in Cygwin, not Linux or macOS or elsewhere. Cygwin is notoriously slow.

    # This is slow on Cygwin, so give Cygwin users a warning
    if($^O eq "cygwin" or $^O eq "msys") {
    ::warning("Finding the maximal command line length. ".
          "This may take up to 1 minute.")
    }

Also note that it only figures this out first time, after which it’s cached on disk.