Redox: Ring Buffers Project Summary

Redox’s ring-buffer project adds an asynchronous communication path between applications and userspace system services, adapting ideas from Linux’s io_uring to Redox’s microkernel design. Applications and services share submission and completion queues plus a shared memory pool, so requests and data can pass without copying or blocking the application. The new redox-ring API, modeled on liburing, supports request batching, shared-buffer allocation, and custom protocols that can also serve general inter-process communication. RamFS and the NVMe driver gained ring support, with tests demonstrating file writes; an asynchronous executor lets drivers process requests as tasks and cleanly cancel pending work when a session ends.

The project reports that ring-based I/O benchmarks run 14-15 times faster than synchronous system-call I/O. Because IPC remains a performance bottleneck, the team also expanded latency benchmarks and made kernel changes that remove redundant locks and lookups and provide a lower-overhead IPC call. Another optimization avoids saving and restoring vector registers during syscall-driven switches, instead zeroing them in accordance with the calling convention. Together, these changes target faster transitions between applications and services as well as more efficient I/O. The work establishes the first ring-buffer implementation in Redox; multi-thread-per-core support for the driver executor remains in progress, and additional device drivers are expected to adopt it.