Despite decades of innovation, existing hash tables fail to achieve peak performance on modern hardware. Built around a relatively simple computation, i.e., a hash function, which in most cases takes only a handful of CPU cycles, hash tables should only be limited by the throughput of the memory subsystem. Unfortunately, due to the inherently random memory access pattern and the contention across multiple threads, existing hash tables spend most of their time waiting for the memory subsystem to serve cache misses and coherence requests.

Rust is the first practical programming language that has the potential to provide fine-grained isolation of untrusted computations at the language level. A combination of zero-overhead safety, i.e., safety without a managed runtime and garbage collection, and a unique ownership discipline enable isolation in systems with tight performance budgets, e.g., databases, network processing frameworks, browsers, and even operating system kernels.

A recent surge of security attacks has triggered a renewed interest in hardware support for isolation. Extended page table switching with VMFUNC, memory protection keys (MPK), and memory tagging extensions (MTE) are just a few of the hardware isolation mechanisms that promise support for low-overhead isolation in recent CPUs. Along with the restored interest in lightweight hardware isolation mechanisms, safe programming languages like Rust has made a leap towards practical, zero-overhead safety implemented without garbage collection.