Maybe I were doing it wrong. The computed directory is my clippy build.

% /usr/bin/du -sch
4.5G    .
4.5G    total
% diskus
4.73 GB (4,727,521,280 bytes)
% hyperfine diskus '/usr/bin/du -sch'
Benchmark #1: diskus
  Time (mean ± σ):     115.8 ms ±  28.6 ms    [User: 2.601 s, System: 0.592 s]
  Range (min … max):    69.1 ms … 156.9 ms    19 runs

Benchmark #2: /usr/bin/du -sch
  Time (mean ± σ):      22.8 ms ±   2.8 ms    [User: 5.5 ms, System: 17.4 ms]
  Range (min … max):    14.2 ms …  26.9 ms    163 runs

Summary
  '/usr/bin/du -sch' ran
    5.07 ± 1.40 times faster than 'diskus'

Meta

• diskus: b2e4cf9 but with cargo update