Data-parallel training: gradient bucketing and overlap
Why DDP feels like magic until you look at the allreduce schedule.
Performance
Tuning TCP BBR and fq on a high-latency link
Switching off loss-based congestion control on a long-fat path, and the fq gotcha for UDP.
A first, honest look at io_uring
Two ring buffers, one syscall, and the mental model that finally made it click.