Vectorization's Empty Promise: Why SIMD Optimizations Rarely Survive Contact with Production Workloads
Modern compilers routinely report successful auto-vectorization, yet engineers frequently discover that the anticipated throughput gains evaporate entirely under real-world conditions. The gap between synthetic benchmark results and production runtime behavior reveals a systematic disconnect between what SIMD instructions theoretically accomplish and what modern CPU pipelines actually deliver. Understanding why vectorization fails in practice requires decoding the interplay between memory topolo