vendor/rayon/tests/par_bridge_recursion.rs

   1 use rayon::prelude::*;
   2 use std::iter::once_with;
   3
   4 const N: usize = 100_000;
   5
   6 #[test]
   7 fn par_bridge_recursion() {
   8     let pool = rayon::ThreadPoolBuilder::new()
   9         .num_threads(10)
  10         .build()
  11         .unwrap();
  12
  13     let seq: Vec<_> = (0..N).map(|i| (i, i.to_string())).collect();
  14
  15     pool.broadcast(|_| {
  16         let mut par: Vec<_> = (0..N)
  17             .into_par_iter()
  18             .flat_map(|i| {
  19                 once_with(move || {
  20                     // Using rayon within the serial iterator creates an opportunity for
  21                     // work-stealing to make par_bridge's mutex accidentally recursive.
  22                     rayon::join(move || i, move || i.to_string())
  23                 })
  24                 .par_bridge()
  25             })
  26             .collect();
  27         par.par_sort_unstable();
  28         assert_eq!(seq, par);
  29     });
  30 }