User Space Buffer Cache with the Bells and Whistles of a Kernel Page Cache
Modern NVMe SSDs push the I/O bottleneck into software. Kernel-bypass frameworks accelerate direct I/O but leave buffered I/O, the dominant mode in practice, unoptimized. We show that small buffered I/O (32 B–4 KB) incurs a 2–15 × kernel overhead and dominates real server and mobile workloads. Existing user-space cache...