rust/src/test/bench/task-perf-jargon-metal-smoke.rs
2014-05-27 11:11:15 -07:00

57 lines
1.9 KiB
Rust

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Test performance of a task "spawn ladder", in which children task have
// many ancestor taskgroups, but with only a few such groups alive at a time.
// Each child task has to enlist as a descendant in each of its ancestor
// groups, but that shouldn't have to happen for already-dead groups.
//
// The filename is a song reference; google it in quotes.
// ignore-pretty very bad with line comments
use std::comm;
use std::os;
use std::task;
use std::uint;
fn child_generation(gens_left: uint, tx: comm::Sender<()>) {
// This used to be O(n^2) in the number of generations that ever existed.
// With this code, only as many generations are alive at a time as tasks
// alive at a time,
spawn(proc() {
if gens_left & 1 == 1 {
task::deschedule(); // shake things up a bit
}
if gens_left > 0 {
child_generation(gens_left - 1, tx); // recurse
} else {
tx.send(())
}
});
}
fn main() {
let args = os::args();
let args = if os::getenv("RUST_BENCH").is_some() {
vec!("".to_string(), "100000".to_string())
} else if args.len() <= 1 {
vec!("".to_string(), "100".to_string())
} else {
args.clone().move_iter().collect()
};
let (tx, rx) = channel();
child_generation(from_str::<uint>(args.get(1).as_slice()).unwrap(), tx);
if rx.recv_opt().is_err() {
fail!("it happened when we slumbered");
}
}