$ cat post/the-function-returned-/-we-kept-it-running-on-hope-/-the-stack-still-traces.md

the function returned / we kept it running on hope / the stack still traces


Title: Debugging Myths and Reality in the Era of WebAssembly


May 2, 2022 was a Wednesday. The morning coffee had just kicked in as I sat down to tackle another issue with our platform. It was one of those days where the tech news felt like it was swirling around me—AI/ML, server-side frameworks, WebAssembly (Wasm), FinOps—it all seemed to be part of the same nebulous cloud of technological change.

Earlier that day, I had read about the FTC’s hefty fine against Twitter for using 2FA phone numbers in ad targeting. It brought back memories of our own internal discussions on data privacy and security, a topic that never seems to go away in tech. Meanwhile, on Hacker News, “I’m all-in on server-side SQLite” was making waves. I chuckled at the thought; it’s been a while since I’ve seen a tool gain such momentum.

But today wasn’t about the broader trends; it was about a specific piece of infrastructure that we were wrestling with: WebAssembly. We had just shipped a new feature using Wasm, and things weren’t exactly going smoothly.

One of our developers had come to me with an issue: the performance of the Wasm module they wrote for handling real-time data processing was lagging behind expectations. The module was supposed to handle streaming data from our IoT devices, but it seemed like every second, we were losing a few milliseconds here and there.

The initial thought was that the problem lay in the Wasm itself—perhaps some inefficiencies or maybe even a bug. But after spending a few hours tracing through the code and profiling with tools like V8’s built-in profiler, I realized that the issue wasn’t with the module but rather how we were integrating it into our system.

Turns out, one of the core myths around Wasm is that it’s a silver bullet for performance. In reality, it still relies heavily on your infrastructure and how you configure it. The culprit turned out to be our network setup—specifically, how we were handling inter-process communication between our Wasm module and the main application.

We had been using local file I/O to pass data between processes, which was inefficient for high-speed streams. After a bit of brainstorming, we shifted to in-memory buffers and optimized our data structures. This change not only improved performance but also simplified our codebase significantly.

Reflecting on this experience, I couldn’t help but think about another Hacker News story from that week: “My students cheated… a lot.” It’s funny how much the tech world mirrors real life—whether it’s students cheating or developers optimizing their systems, there are always trade-offs and challenges to face.

As we moved forward with these optimizations, another thought crept into my mind. The DORA metrics for software delivery efficiency were increasingly becoming part of our lexicon. We focused not just on code quality but also on deployment speed and reliability. It was a reminder that while technology is evolving rapidly, the fundamental principles of building reliable systems remain constant.

This day, like many others, highlighted both the opportunities and the challenges in today’s tech landscape. From AI/ML to WebAssembly, each layer presents new problems to solve, but with persistence and an understanding of the underlying infrastructure, we can overcome them.

So here’s to another day in the ever-changing world of platform engineering! Let’s keep pushing boundaries, learning from our mistakes, and optimizing for both performance and simplicity. After all, as I debugged my way through that Wasm module, I found myself saying a silent thank you to the tech community—whether it was Twitter or server-side SQLite—all these little sparks help illuminate the path forward.


That’s how you make progress in this era of constant change. It’s not just about shipping code; it’s about understanding the myths and realities that surround our tools and techniques, and then finding the right solutions for your specific challenges.