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Systems & Performance

The most popular blog posts about systems & performance on Hacker News. 518 posts.

2026
153

Epoll vs. io_uring in Linux

First, I want to tell you how exactly I got to this point and why I started researching different options for handling asynchronous I/O on Linux… Last year, my students and I built a reverse proxy server called TinyGate. It was super simple, worker-based, and it basically worked well. Of course, I didn’t expect it to…

155

WASI 0.3

WASI 0.3 is official, and async is now native to WebAssembly Components. The WASI Subgroup voted to ratify WASI 0.3.0, rebasing WASI onto the WebAssembly Component Model’s async primitives. The 0.3.0 specification is now stable, and runt...

157

Things Unix can do atomically (2010)

This is a catalog of things UNIX-like/POSIX-compliant operating systems can do atomically, making them useful as building blocks for thread-safe and multi-process-safe programs without mutexes or read/write locks. The list is by no means exhaustive and I expect it to be updated frequently for the foreseeable future.

158

What async promised and what it delivered

The async/await saga is a story where each chapter solves the previous chapter's worst problem while introducing new structural costs. The sequential syntax that made async code readable also obscures the thing that matters: which operations actually depend on each other.

164

Who is vfmaddrnd231pd?

vfmaddrnd231pd is a unique instruction from the FMA instruction set. Most instructions in that set have mnemonics like vfmadd231pd, but here rnd means something very specific. The Intel Software Development Manual documents it as: VFMADDRND231PD – Fused Multiply-Add of Packed Double-Precision Floating-Point Values…

172

What is malloc doing, anyway?

malloc has a very nice and simple interface: you ask for a certain amount of memory, and you’re given a void pointer to your block of contiguous bytes that’s been magicked into existence. Once you’re done with it, you call free with the same pointer and the memory disappears into the ether.