[ole_tange]

Rust-parallel _is_ fast, and there is clearly a niche here, that GNU Parallel is unlikely to fill: By design GNU Parallel will never require a compiler; this is so you can use GNU Parallel on old systems with no compilers (Think an old, dusty AIX-box that people have forgotten the root password to). This design decision limits how fast GNU Parallel can be compared to compiled alternatives.

But the main problem with rust-parallel is that it is not compatible with GNU Parallel (and according to the author, it probably never will be 100% compatible). If you use rust-parallel to walk through GNU Parallel's tutorial (man parallel_tutorial) you will see it fails very quickly.

(Full disclosure: I am the author of GNU Parallel. I fully support building other parallelizing tools, but to avoid user confusion, I would recommend calling them something other than 'parallel' if they are not actually compatible with GNU Parallel. History has shown that using the same name will lead to a lot of unnecessary grief: e.g. GNU Parallel vs. Parallel from moreutils).