Recent content in Home on Jose Fernandez
I created bpftop at Netflix in early 2024 as a command-line tool for monitoring eBPF programs in real time. It was released under the Apache 2.0 license on the Netflix GitHub org, and it quickly gained adoption in the eBPF and Linux communities, getting coverage from LWN.net , InfoQ , and The New Stack . It’s now packaged in 19 Linux distributions including Ubuntu, Fedora, Debian, Arch…
When I introduced mdserve last year, I blogged about it as a tool for AI coding agent workflows, but the project itself never said that. The README called it a “fast markdown preview server with live reload and theme support.” Generic on purpose. People started using it for things I never intended: replacing MkDocs, hosting documentation. With v1.0 , I’m dropping the ambiguity.…
Coding agents often produce better results when you don’t ask them to write code immediately. If you jump straight to execution without thinking through the design, the code quality suffers. I’ve found it better to whiteboard the problem first. It’s like pairing with a senior engineer. You enter a room, map out the problem space, explore solutions, and sketch architectural…
As coding LLM agents get better, I find myself using IDEs less and less. These days, my workflow is mostly Claude Code and Neovim. I don’t think I need a full IDE anymore for most work. But there was one thing I missed from IDEs: built-in markdown preview. AI-assisted coding involves a lot of markdown work, and instant visual feedback is valuable. The Problem Most markdown preview tools are…
I recently co-authored a post on the Netflix Tech Blog where we detailed how we’re continuously monitoring the Linux scheduler using eBPF to enhance system observability. By instrumenting the scheduler, we gain real-time insights into CPU resource contention and noisy neighbor issues, all with minimal overhead. This method allows for deeper visibility into Linux performance, improving…
Packaging a Rust program for Fedora may seem daunting initially, but it’s more straightforward than expected, thanks to excellent documentation, Rust-specific tooling, and a helpful community. Over the past two months, I packaged bpftop , a process monitor for eBPF programs. While there were some specific considerations with Rust, the process was manageable. In this post, I’ll share…
I’m a systems engineer at Anthropic . I contribute to the Linux kernel , created bpftop , and work deep in the stack with eBPF and Rust. Contact You can reach me at: me@jrfernandez.com Connect with me on: GitHub Twitter
The assistant is a personal AI assistant that I, Jose Fernandez, run on my home server. It has its own dedicated phone number through Twilio, separate from my personal phone, and it can also send email on my behalf. It replies to people who text that number, sends me reminders, and occasionally reaches out to a business or contact on my behalf. Replies may be generated by an automated AI assistant…
This policy describes how data sent to the Jose Fernandez Personal Assistant, a personal SMS line I, Jose Fernandez, operate on a dedicated Twilio number, is handled. Data collected via SMS When you text the number, the assistant may collect: Your phone number. The content of your messages. Timestamps of when messages are sent and received. Any media you send, such as images. How the data is used…
Program description The Jose Fernandez Personal Assistant is a personal SMS line I, Jose Fernandez, operate on a dedicated Twilio phone number, separate from my personal phone. It handles conversational text messages on my behalf, and replies may be generated by an automated AI assistant. Message samples Messages identify the sender. Examples: Reply to someone who texted in: “Hi, this is…
Program name Jose Fernandez Personal Assistant Description This is a personal SMS line I, Jose Fernandez, operate on a dedicated Twilio phone number, separate from my personal phone. Replies may be generated by an automated AI assistant acting on my behalf. Message frequency Messaging is conversational and depends on your interaction with the line. There is no fixed schedule. This is a low-volume…
bpftop is a monitoring tool I created to provide real-time insights into the performance of eBPF programs. Read more about it in the blog post on the Netflix Tech Blog. Media coverage InfoQ - https://www.infoq.com/news/2024/03/netflix-launches-bpftop/ LWN.net - https://lwn.net/Articles/963767/ The New Stack - https://thenewstack.io/netflix-releases-bpftop-an-ebpf-based-application-monitor/…
Sign up to receive text messages from the Jose Fernandez Personal Assistant , a personal SMS line for coordinating household reminders and messages. Enter your mobile number below and check the consent box to opt in. This is a low-volume, personal line — not a marketing or promotional service.
I started contributing to the Linux kernel in 2024. My primary focus is in the eBPF subsystem. I have submitted to the following patches: bpf: Improve program stats run-time calculation Released in v6.10 drm/amd/display: Fix division by zero in setup_dsc_config Released in v6.10 bpf: add bpf_task_get_cgroup kfunc Rejected kbuild: control extra pacman packages with PACMAN_EXTRAPACKAGES Released in…
mdserve is a fast, lightweight markdown preview server I created for terminal-based workflows. Read more about it in my blog post . Key Features Zero dependencies: Just a single binary Lightning fast: Built in Rust Live reload: Auto-refreshes when files change Beautiful themes: Built-in Catppuccin support (Latte, Macchiato, Mocha) plus additional themes Installation macOS: brew install mdserve…