3 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
4 // file at the top-level directory of this distribution and at
5 // http://rust-lang.org/COPYRIGHT.
7 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
8 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
9 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
10 // option. This file may not be copied, modified, or distributed
11 // except according to those terms.
13 // Test performance of a task "spawn ladder", in which children task have
14 // many ancestor taskgroups, but with only a few such groups alive at a time.
15 // Each child task has to enlist as a descendant in each of its ancestor
16 // groups, but that shouldn't have to happen for already-dead groups.
18 // The filename is a song reference; google it in quotes.
25 fn child_generation(gens_left: uint, tx: comm::Sender<()>) {
26 // This used to be O(n^2) in the number of generations that ever existed.
27 // With this code, only as many generations are alive at a time as tasks
30 if gens_left & 1 == 1 {
31 task::deschedule(); // shake things up a bit
34 child_generation(gens_left - 1, tx); // recurse
42 let args = os::args();
43 let args = if os::getenv("RUST_BENCH").is_some() {
45 } else if args.len() <= 1 {
48 args.clone().move_iter().collect()
51 let (tx, rx) = channel();
52 child_generation(from_str::<uint>(*args.get(1)).unwrap(), tx);
53 if rx.recv_opt().is_err() {
54 fail!("it happened when we slumbered");