关于 Monoio 的介绍：一个高性能的 Rust 运行时

Background: A potential client asked to build the fastest HTTP proxy in Rust using Monoio. After the client decided not to move forward, the author decided to document findings as Monoio has limited documentation. This post will introduce Monoio and explain its technical advantages.
What is Monoio: An asynchronous runtime for Rust similar to Tokio but with different priorities and architecture. Created by ByteDance, it's a thread-per-core runtime using io_uring on Linux for maximum performance. It eliminates thread synchronization for certain workloads.
What Makes Monoio Different:
- Thread-per-core Architecture: Each thread executes its own tasks without work stealing, has a thread-local task queue, minimizes cross-thread operations, and tasks stay on the same thread. Similar to high-performance servers.
- io_uring Integration: Designed to leverage io_uring, a new Linux kernel interface that reduces syscall overhead and context switches for I/O-heavy workloads. It prioritizes io_uring and has fallback support for epoll and kqueue.
- Unique I/O Abstraction: In Monoio, you give ownership of the buffer to the runtime during I/O operations, while in Tokio/std, you provide a reference. This is necessary for io_uring as the kernel needs direct access to buffers.
What is io_uring and Why Does it Matter: io_uring is a significant advancement in I/O operations in Linux. It reduces syscalls, enables batched operations, true asynchronous file I/O, and zero-copy operations.
When is Monoio Faster: Monoio excels in network-intensive, file I/O heavy, predictable task distribution, and high throughput, low latency services. But it may not be the best for CPU-bound workloads or unpredictable task distribution.
Simple Monoio Applications:
- Basic Single-Threaded Example: Shows async runtime without networking, using #[monoio::main] to set up runtime and spawn tasks. All tasks execute concurrently in a single thread.
- Multi-Core Thread-Per-Core Example (Using macros): Demonstrates using multiple cores with Monoio's built-in multi-threading support. The worker_threads parameter runs the entire program on each worker thread.
- Multi-Core Thread-Per-Core Example (Production-Ready): In a production environment, creates a thread for each available CPU core and binds each thread to its specific core. Offers advantages like CPU affinity, error handling, full control, and resource utilization.
Conclusion: Monoio is an exciting advancement in Rust async runtime for I/O-bound server applications. It offers performance benefits with io_uring and a thread-per-core architecture. In the following blog series, the author will build a basic HTTP server and benchmark it against other implementations.