[Nyan]

Nice work - thanks for your efforts!

Yeah, the compute complexity for Reed Solomon is generally O(size_of_input * number_of_recovery_blocks)

If you don't specify the number of blocks, par2cmdline defaults to 2000, so at 25%, it's generating 500 parity blocks, which is obviously much slower than what you're generating with the other tools.

Having said that, PAR2 is generally aimed at use cases with hundreds/thousands of parity blocks, so it's going to be at a disadvantage if you're generating less than 10 - which your benchmark shows.