I built a 3.9M ops/sec io_uring KV server in C++ — ~90% of the code written by AI

I’ve been experimenting with high-performance networking on Linux and built a small project called dalahash.

It’s an in-memory key-value server using a thread-per-core architecture with io_uring.

Design:

• worker thread per CPU (pinned) and RX/TX queue
• one io_uring instance per worker
• SO_REUSEPORT listener sharding
• lock-free shared KV store
• Redis and Memcached protocols (small subset)

Quick benchmark using memtier_benchmark:

• ~3.9M ops/sec
• 230 µs average client latency
• 823 µs p99.99 client latency
• ~18.8M ops/sec with pipelining

About 90% of the code was written using AI agents (OpenAI GPT-5.3-Codex and Claude Opus 4.6). I mainly focused on the architecture and reviewed the generated code.

Repo:
https://github.com/joakimthun/dalahash

Curious what people working with io_uring or high-performance servers think.