以下代码在调用
read_line(..)
时运行速度要慢得多,而不是 lines()
。
您无法在playground中运行它,但对我来说,它会打印以下内容。lines() took Duration { secs: 0, nanos: 41660031 }
read_line() took Duration { secs: 2, nanos: 379397138 }
Lines的实现方式基本上就是我所写的(但更多!)为什么会有这样的差异?
use std::net::{TcpListener, TcpStream};
use std::io::{BufRead, BufReader, Write};
use std::thread;
fn main() {
let listener = TcpListener::bind("127.0.0.1:80")
.expect("listen failed");
thread::spawn(move || {
for stream in listener.incoming() {
let mut stream = stream.unwrap();
thread::spawn(move || {
for x in 1..1000 + 1 {
stream.write_all(format!("{}\n", x).as_bytes())
.expect("write failed");
}
});
}
});
let start_a = std::time::Instant::now();
{
let stream_a = TcpStream::connect("127.0.0.1:80")
.expect("connect_a failed");
let br = BufReader::new(stream_a);
for l in br.lines() {
println!("{}", l.unwrap());
}
}
let end_a = std::time::Instant::now();
let start_b = std::time::Instant::now();
{
let stream_b = TcpStream::connect("127.0.0.1:80")
.expect("connect_b failed");
let mut br = BufReader::new(stream_b);
let mut s = String::with_capacity(10);
while br.read_line(&mut s).unwrap_or(0) > 0 {
println!("{}", s);
}
}
let end_b = std::time::Instant::now();
let dur_a = end_a - start_a;
let dur_b = end_b - start_b;
println!("lines() took {:?}", dur_a);
println!("read_line() took {:?}", dur_b);
}
--release
标志进行测试?每当有人说 Rust 代码不够快时,这通常是最常见的问题。 - Shepmaster