W0 synthetic fp16 matvec capture — 2026-10-22, Apple M3
Command: nice -n 10 code/build/ch07_bw
System load average before capture: 4.63; memory pressure free: 51%.
GPU utilization sampled immediately after run via ioreg: 35% (not idle).
Statistic: median of five wall-time runs, including submit and wait; not GPU time.
No model file or weights opened.

synthetic fp16 matvec: 1024 x 4096, median-of-5 0.585 ms wall, 14.3 GB/s, y[0]=4096
