600 instructions or 599: nothing guarantees which, and it flips atomics
matiasgoldberg · x · 2026-11-01
matiasgoldberg clarifies his earlier point to mike64t: the extreme example was illustrative, not literal. The core argument is that GPU code is a big fat instruction blob, and nothing guarantees whether it takes 600 or 599 instructions — and that difference will change the outcome of an atomic operation.
Related event: GPU Experts Debate Whether Driver Versions Break CUDA Atomic Determinism(9 posts)→
More from Infra
- Meme: writing an LLVM backend for a fully undocumented GPU architecture to ditch closed-source nvcc — mike64_t · 2026-11-01
- Enterprises are distilling domain models, cutting costs from dollars to cents with no accuracy loss — himanshustwts · 2026-11-01
- Prediction: Local Models Will Be the Biggest AI Story of 2027, Disrupting Inference Business — ZeYanjie · 2026-11-01
- Reddit bench: EPYC + multi-3090 rig runs Qwen Q8 at 94 tok/s with near-linear scaling to 8 streams — sleight42 · 2026-11-01
- RAM up 7x to $429 in 18 months as Sam Altman says the invisible hand is failing — aakashgupta · 2026-11-01
- Blogger estimates xAI on track for $100B ARR by end-2026 as datacenter builds move up — mitchdeg · 2026-11-01