Hi everyone! Recently, I came across an interesting question online: Why is Go’s performance not as good as Rust’s?
After all, Go has always been marketed for its simplicity and efficiency, while Rust has gained attention for its safety and performance. So, how come Rust outperforms Go in terms of performance?
1. Different Language Design Philosophies
Firstly, Go’s design philosophy is “less is more”. It prioritizes development speed, aiming to solve engineering problems in concurrent scenarios from the very beginning. Thus, Go’s garbage collection (GC) mechanism, simple syntax design, and built-in goroutines all serve the purpose of quickly building efficient services. It seems that Go is more like C’s successor—a language that is straightforward and easy to use.
Rust, on the other hand, is entirely different. Its goal is to balance performance and safety, even willing to sacrifice some convenience (like lifecycle management and ownership models) for these two points. This allows Rust to approach or even exceed the performance of C and C++ in many cases, as evidenced by the efficient machine code it generates.
2. Memory Management
Go uses a garbage collection mechanism (Garbage Collection, GC), which is a blessing in concurrent programming, as developers hardly need to worry about memory management. When writing code, you only need to focus on business logic, leaving the rest to the GC. However, the biggest problem with GC is that it inevitably introduces pauses, especially in high-performance scenarios where the overhead of GC becomes apparent over time.
Rust, on the other hand, has eschewed GC in favor of manual memory management that is closer to C++, but with an added “ownership system”. This system allows Rust’s memory management to be completed at compile time, meaning that when the code runs, there is almost no additional overhead for memory allocation and deallocation. The code you write can generate execution effects very close to native machine instructions, which directly boosts performance.
In simple terms, Go trades development speed for GC, while Rust sacrifices developer convenience for runtime performance. One is developer-friendly, while the other directly confronts the hardware; which one is faster? Of course, it’s Rust.
3. Concurrency Models: Goroutine vs Async/Await
In terms of concurrent programming, Go’s goroutine model can be said to completely outclass traditional thread pools. Writing concurrent code in Go feels like playing with building blocks; you just need to call go func(), and the system will automatically schedule it for you, which is incredibly satisfying.
Rust’s concurrency model is entirely different. It relies on async/await and Futures, which are not as user-friendly as native goroutines. However, it has a significant advantage: no runtime overhead. Rust’s concurrency almost entirely relies on compile-time generation of efficient state machines, making runtime performance very close to hand-written multithreaded code.
In this regard, both have their merits. If you need ultra-high performance with a few critical threads, such as in video processing or game engines, Rust’s approach is clearly more suitable; but if you need to manage hundreds or thousands of lightweight tasks, like in network services, Go’s goroutines are simpler.
4. Compiler Optimization
Rust and Go’s compilers also have their own strengths. Rust’s compiler (based on LLVM) can perform deep optimizations, such as common function inlining, loop unrolling, and various advanced instruction set optimizations. Go’s compiler, on the other hand, focuses more on fast compilation, with relatively less aggressive optimization capabilities. This means that the binary code generated by Rust is usually more efficient, but the compilation time is longer.
For example, let’s consider a piece of code that sums an array:
fn sum_array(arr: &[i32]) -> i32 {
arr.iter().sum()
}
The Rust compiler will attempt to inline the implementations of iter() and sum(), generating highly optimized assembly code for specific array sizes.
In Go, a similar piece of code would look like this:
func sumArray(arr []int) int {
sum := 0
for _, v := range arr {
sum += v
}
return sum
}
While Go’s compiler can also generate decent code, it typically won’t
