设备是 aws c7gn.metal arm 架构 64 核心。
1 个 sender ，n 个 receiver 。发送时间戳。 设置 linux route 走 lo 网卡。
当 receiver20 个以内时。延迟大概是 40us 以内可控。 当 receiver 个数增加到 50-100 个以后， 延迟逐渐上升到 100~200us 以上。cpu 仍然占用很低，延迟显著增加，这是为什么呢？
求解 如何能让 50+ receiver 同时接收， 还能保持 50us 以下延迟？
use serde::{Deserialize, Serialize};
use std::net::{Ipv4Addr, SocketAddrV4};
const MULTICAST_ADDR: Ipv4Addr = Ipv4Addr::new(239, 255, 0, 1);
const MULTICAST_PORT: u16 = 3001;
const BIND_ADDR: Ipv4Addr = Ipv4Addr::LOCALHOST;
pub fn timestamp16() -> u128 {
SystemTime::now()
.duration_since(UNIX_EPOCH)
.unwrap()
.as_micros()
}
/// Networking options.
#[derive(argh::FromArgs)]
struct Args {
/// multicast address that the socket must join
#[argh(option, short = 'a', default = "MULTICAST_ADDR")]
addr: Ipv4Addr,
/// specific port to bind the socket to
#[argh(option, short = 'p', default = "MULTICAST_PORT")]
port: u16,
/// whether or not to allow the UDP socket
/// to be reused by another application
#[argh(switch)]
is_sender: bool,
}
fn main() -> std::io::Result {
init_logger();
use socket2::{Domain, Protocol, Socket, Type};
let Args {
addr,
port,
is_sender,
} = argh::from_env();
println!("{} {} is_sender: {}", addr, port, is_sender);
let socket = Socket::new(Domain::IPV4, Type::DGRAM, Some(Protocol::UDP))?;
socket.set_nonblocking(true)?;
socket.set_reuse_address(true)?;
socket.set_reuse_port(true)?;
socket.set_multicast_loop_v4(true)?;
socket.set_multicast_ttl_v4(1)?;
socket.join_multicast_v4(&addr, &Ipv4Addr::LOCALHOST)?;
let fin_addr = SocketAddrV4::new(addr, port);
if is_sender {
socket.bind(&SocketAddrV4::new(Ipv4Addr::LOCALHOST, port).into())?;
} else {
socket.bind(&SocketAddrV4::new(Ipv4Addr::UNSPECIFIED, port).into())?;
}
let runtime = tokio::runtime::Builder::new_current_thread()
.thread_name("network")
.enable_all()
.build()?;
let udp = {
let _guard = runtime.enter();
tokio::net::UdpSocket::from_std(socket.into())?
};
runtime.block_on(async move {
let mut interval = tokio::time::interval(tokio::time::Duration::from_millis(1000));
if is_sender == false {
interval = tokio::time::interval(tokio::time::Duration::from_secs(60 * 60 * 24));
}
interval.tick().await;
let mut buf = [0; 16];
loop {
tokio::select! {
recv_res = udp.recv_from(&mut buf) => {
let (count, remote_addr) = recv_res.expect("cannot receive from socket");
let parsed = u128::from_be_bytes(buf[..count].try_into().unwrap());
let cost = timestamp16() - parsed;
println!("{:?}", );!("recv {remote_addr} {parsed} {count} {cost}")
}
_ = interval.tick() => {
let cur = timestamp16();
let input = cur.to_be_bytes();
udp.send_to(&input, fin_addr).await.expect("cannot send message to socket");
println!("{:?}", );!("send: {}", cur);
}
}
}
});
Ok(())
}
