19 releases

0.1.36 Feb 13, 2022
0.1.35 Feb 8, 2022
0.1.30 Jan 28, 2022
0.1.3 Dec 30, 2021

#631 in Concurrency


Used in 2 crates

MIT/Apache

595KB
13K SLoC

cogo

Cogo is a high-performance library for programming stackful coroutines with which you can easily develop and maintain massive concurrent programs. It can be thought as the Rust version of the popular [Goroutine][go].

Initial code frok from May and we add Many improvements(Inspired by Golang, parking_lot and crossbeam) and more...

Performance

per

cogo crates

Cogo Powerful standard library

  • cogo/std/queue Basic queue data structures
  • cogo/std/sync Includes Mutex/RwLock/WaitGroup/Semphore/chan!()/chan!(1000)...and more..
  • cogo/std/defer Defers evaluation of a block of code until the end of the scope.
  • cogo/std/map Provides the same concurrency map as Golang, with SyncHashMap and SyncBtreeMap.It is suitable for concurrent environments with too many reads and too few writes
  • cogo/std/time Improve the implementation of a high performance time
  • cogo/std/lazy Thread/coroutine safe global variable,Lazy struct,OnceCell

Crates based on cogo implementation

  • cogo-http High-performance coroutine HTTP server and client
  • cdbc Database Drivers include mysql, Postgres, AND SQLite
  • fast_log High-performance log impl
  • cogo-redis TODO: an redis client.
  • cogo-grpc TODO: an grpc server/client.

Features

  • The stackful coroutine implementation is based on [generator][generator];

  • Support schedule on a configurable number of threads for multi-core systems;

  • Support coroutine version of a local storage ([CLS][cls]);

  • Support efficient asynchronous network I/O;

  • Support efficient timer management;

  • Support standard synchronization primitives, a semaphore, an MPMC channel, etc;

  • Support cancellation of coroutines;

  • Support graceful panic handling that will not affect other coroutines;

  • Support scoped coroutine creation;

  • Support general selection for all the coroutine API;

  • All the coroutine API are compatible with the standard library semantics;

  • All the coroutine API can be safely called in multi-threaded context;

  • Both stable, beta, and nightly channels are supported;

  • x86_64 GNU/Linux, x86_64 Windows, x86_64 Mac, aarch64 Linux OS are supported.

  • Support High performance chan(like golang)

  • Support WaitGroup Support(like golang)

  • Support defer!() (like golang)

  • Support Rustls

  • Support Time (like golang)

  • Support error/err!() (like golang)

  • Support select match Ok(v)/Err(e) (like golang)

  • Support Lazy/OnceCell

  • Support SyncMap(like golang)

  • Support Ticker(like golang)

Usage

cogo = "0.1"

A naive echo server implemented with Cogo:

#[macro_use]
extern crate cogo;

use cogo::net::TcpListener;
use std::io::{Read, Write};

fn main() {
    let listener = TcpListener::bind("127.0.0.1:8000").unwrap();
    while let Ok((mut stream, _)) = listener.accept() {
        go!(move || {
            let mut buf = vec![0; 1024 * 16]; // alloc in heap!
            while let Ok(n) = stream.read(&mut buf) {
                if n == 0 {
                    break;
                }
                stream.write_all(&buf[0..n]).unwrap();
            }
        });
    }
}

More examples

The I/O heavy bound examples

Caveat

There is a detailed [document][caveat] that describes Cogo's main restrictions. In general, there are four things you should follow when writing programs that use coroutines:

  • Don't call thread-blocking API (It will hurt the performance);
  • Carefully use Thread Local Storage (access TLS in coroutine might trigger undefined behavior).

It's considered unsafe with the following pattern:

set_tls();
// Or another coroutine API that would cause scheduling:
coroutine::yield_now(); 
use_tls();

but it's safe if your code is not sensitive about the previous state of TLS. Or there is no coroutines scheduling between set TLS and use TLS.

  • Don't run CPU bound tasks for long time, but it's ok if you don't care about fairness;
  • Don't exceed the coroutine stack. There is a guard page for each coroutine stack. When stack overflow occurs, it will trigger segment fault error.

Note:

The first three rules are common when using cooperative asynchronous libraries in Rust. Even using a futures-based system also have these limitations. So what you should really focus on is a coroutine stack size, make sure it's big enough for your applications.

How to tune a stack size

cogo::config().set_stack_size(8*1024);//default is 4k=4*1024,Multiple of 4kb is recommended
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Dependencies

~4–30MB
~388K SLoC