Table of Contents
Choosing between Rust and C++ is a foundational decision for HFT firms. While C++ has dominated for decades, Rust offers performance parity with superior safety guarantees. This analysis compares both based on the latency and reliability requirements of modern trading systems.
Performance Benchmarks
- ✦ Latency: Both languages operate in the ~200-450ns range, with C++ holding a marginal lead in absolute minimum latency and Rust providing more predictable P99 latency due to memory safety features.
- ✦ Optimization: Both provide full hardware-level control (SIMD, cache-line alignment), but Rust's compiler generates more defensive machine code by default.
The Memory Safety Gap
Memory safety bugs-specifically use-after-free and buffer overflows-are responsible for the majority of critical production crashes in trading. Unlike C++, where these are runtime risks requiring extensive sanitizers, Rust enforces memory safety at compile-time. For HFT, this means eliminating a class of bugs that have historically caused millions in trading losses.
Concurrency Paradigms
- ✦ C++: Offers immense power but relies on developer discipline to avoid data races.
- ✦ Rust: 'Fearless Concurrency'-the compiler prevents data races at compile-time, allowing teams to refactor complex trading logic with confidence.
Engineering Verdict: HFT Strategic Roadmap
- ✦ Greenfield Systems: Choose Rust for native safety and modern tooling.
- ✦ Legacy C++ Maintenance: Stay with C++ to avoid the cost of full rewrites.
- ✦ Hybrid Approach: Use Rust via FFI for new, safety-critical modules within your existing C++ stack.
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