I found your benchmarks and noticed you refer to borgbackup 1.1.0b6 as "attic".

While attic is the project borg was forked from, it has developped way beyond attic meanwhile (and we're not finished yet). So maybe rather refer to it as borgbackup. While borg can import attic repos, the repo format is intentionally different (changed magic value).

Attic hasn't developped at all since the fork (still at 0.16) and has known/unfixed issues, so guess you do not need to include it in your benchmark any more.