Performance on mc · noteshttps://hk.crepuscule.uk/tags/performance/Recent content in Performance on mc · notesHugoen-usTue, 19 May 2026 17:40:00 +0800Data-parallel training: gradient bucketing and overlaphttps://hk.crepuscule.uk/posts/grad-bucketing/Tue, 19 May 2026 17:40:00 +0800https://hk.crepuscule.uk/posts/grad-bucketing/Why DDP feels like magic until you look at the allreduce schedule.Tuning TCP BBR and fq on a high-latency linkhttps://hk.crepuscule.uk/posts/bbr/Mon, 03 Nov 2025 22:15:00 +0800https://hk.crepuscule.uk/posts/bbr/Switching off loss-based congestion control on a long-fat path, and the fq gotcha for UDP.A first, honest look at io_uringhttps://hk.crepuscule.uk/posts/io-uring/Thu, 22 May 2025 20:40:00 +0800https://hk.crepuscule.uk/posts/io-uring/Two ring buffers, one syscall, and the mental model that finally made it click.