Fernando Simões

Welcome to my personal website! This is where I share debugging stories and other explorations into kernels, databases, runtimes, and performance. Feel free to reach me at frn@frn.sh.

Things I'm doing

Working on performance, infrastructure, reliability. I enjoy measuring things
Reading a bunch of computer science papers
Linux kernel and postgres internals take up most of my time these days
Moving to Portugal in December 2026

Posts

Most of these are me trying to understand something that caught my interest, or to reproduce a production incident in a more controlled environment.

12 Jun, 2026 Tracing an 8kb Postgres read
03 Apr, 2026 What /proc sees in 19 MiB
21 Mar, 2026 Where did 400 MiB go?
11 Dec, 2025 108,725 forks
30 Oct, 2025 Breaking what a program is
08 Apr, 2025 Sigterm a D state process
15 Feb, 2024 The cost of not measuring