Traceflock

a real-time Linux process monitoring tool powered by eBPF. It works like htop but with deeper kernel-level visibility .

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Inspiration

Modern Linux systems spawn thousands of processes in the background, yet visibility into their real-time lifecycle is still surprisingly limited. Tools like htop and ps are great for snapshots, but they don’t show the story of a process — how it was born, what it turned into, and when it died. I wanted a tool that felt alive: something that could trace the flock of processes moving through the system with clarity, beauty, and precision. eBPF gave me the perfect foundation to build such a tool.

What it does

TraceFlock is a real-time, interactive process lifecycle monitor powered by eBPF. It:

  • Captures fork, exec, and exit events directly from kernel tracepoints
  • Builds a live process tree that updates as events occur
  • Tracks memory usage, states, and process age
  • Presents everything in a beautiful htop-style TUI
  • Offers filters, keyboard controls, and color-coded visualization
  • Runs efficiently with minimal overhead thanks to eBPF

It’s like watching your system breathe — every process in motion, visualized instantly.

How I built it

TraceFlock is composed of three major layers working together:

1. eBPF Kernel Programs

I implemented tracepoint hooks for:

  • sched_process_fork
  • sched_process_exec
  • sched_process_exit

These lightweight programs package event data and stream it to user space using a ring buffer. I used libbpf to load, attach, and manage these eBPF programs.

2. User-Space Core

The main application:

  • Initializes and orchestrates all subsystems
  • Polls and processes ring buffer events
  • Maintains a dynamic process table and parent-child relationships
  • Fetches extra details from /proc (command names, states, memory usage)
  • Handles signals and manages clean shutdowns

3. Terminal User Interface

Using raw terminal control (no ncurses), the UI:

  • Renders a live updating, color-coded table of processes
  • Displays a sticky header with dynamic system stats
  • Draws ASCII process trees and icons
  • Handles keyboard input for filtering and navigation

The result is a smooth, responsive, and visually appealing TUI.

Challenges I ran into

  • eBPF verifier errors The verifier is extremely strict. Every pointer access, map lookup, and code path had to be carefully controlled.

  • Synchronizing kernel events with user-space state Fork/exec/exit events can arrive very fast and occasionally out of order. Maintaining a correct process tree required continuous reconciliation with /proc.

  • Building a flicker-free TUI from scratch Handling terminal resizing, non-blocking input, efficient screen redraws, and raw ANSI control sequences was a challenge.

  • Avoiding ring buffer event drops under heavy load Busy systems can generate thousands of events per second. I had to tune buffer sizes and optimize the event-processing loop.

  • Distribution-specific quirks Kernel headers, libbpf versions, and BTF availability vary widely across distros, making development and testing more complex.

Accomplishments I’m proud of

  • Implementing a fully functional real-time eBPF tracing tool from scratch
  • Designing a clean, modular architecture that’s easy to extend
  • Creating a fast, flicker-free TUI without external UI libraries
  • Keeping CPU and memory usage consistently low
  • Turning raw kernel events into something intuitive and beautiful
  • Building a tool that makes process lifecycle tracing genuinely enjoyable to watch

What I learned

  • Deep insights into eBPF, tracepoints, libbpf, BTF, and kernel architecture
  • How Linux handles the process lifecycle internally
  • Effective strategies for real-time visualization in terminal environments
  • The importance of modular interfaces and clean subsystem boundaries
  • How to debug eBPF verifier errors (and how unforgiving they can be)
  • That building developer tools is incredibly rewarding when everything finally clicks

What’s next for TraceFlock

There’s a lot more I want to build:

  • Network and file I/O activity tracing
  • Export/logging mode for external analysis
  • Remote monitoring agent

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