Hacker News

The Front Page

Vol. I July 17, 2026 Price: A cup of coffee

3h, 18p, 3 comments

Faster binary search: from compiled code to mechanical sympathy

Itamar Turner‑Trauring describes how he accelerated a key step in scikit‑learn’s gradient‑histogram boosting—assigning floating‑point values to 255 buckets—by rewriting the binary‑search bucketizer in Rust and applying “mechanical sympathy.” Starting from a standard compiled binary search, he eliminates unpredictable branch mispredictions with a branch‑less implementation, removes bounds‑check overhead using unsafe code, pre‑computes halving steps, and finally enables auto‑vectorization and SIMD by targeting modern x86‑64 CPUs and rearranging loops for better data locality. These optimizations reduce branch count from 27 to 0 per value, raise instructions‑per‑cycle, and cut runtime from ~46 ms to ~7 ms on a million‑element dataset—a six‑fold speed‑up. The article also suggests further gains via parallelism and recommends resources for learning CPU‑aware performance tuning.

14h, 84p, 25 comments

Old Icons

Old icons examines the evolution of early Macintosh application icons, noting that original Mac icons were 32×32 px black‑and‑white images featuring tilted rectangles and hand symbols to denote active apps. The article references classic icons such as MacWrite, MacPaint, MacDraw, and HyperCard, and discusses how third‑party software like Aldus PageMaker, QuarkXPress, and THINK’s Pascal editor adapted or abandoned these motifs. It argues that the constraints of early icon design fostered whimsical elements—hand shapes protruding from the rectangles—that modern “squircle jail” debates echo, and observes that as the Mac interface matured (including the introduction of the Dock), these visual cues became less necessary, leading to more diverse icon styles.