Systems & Kernel Notes https://blog.870919.xyz/ Engineering notes on Linux kernel networking, congestion control, distributed consensus, and storage internals. en-us Mon, 19 Oct 2026 10:00:00 +0000 Dissecting TCP BBR and Pacing Queue Dynamics on High-BDP Cross-Border Links https://blog.870919.xyz/posts/bbrv3-tcp-low-latency-tuning.html https://blog.870919.xyz/posts/bbrv3-tcp-low-latency-tuning.html Mon, 19 Oct 2026 10:00:00 +0000 An empirical look at how fq pacing, tcp_notsent_lowat, and disabling slow-start-after-idle eliminate burst-induced tail latency. Zero-Copy L4 Load Balancing and Socket Splicing with eBPF SOCKMAP and sk_msg https://blog.870919.xyz/posts/ebpf-sockmap-zero-copy-l4.html https://blog.870919.xyz/posts/ebpf-sockmap-zero-copy-l4.html Mon, 28 Sep 2026 10:00:00 +0000 Bypassing the full sk_buff netfilter traversal when chaining local TCP proxies on Linux 6.12+. Mitigating Tail Latency in Raft-Backed Metadata Stores: PreVote, ReadIndex, and Async WAL https://blog.870919.xyz/posts/raft-consensus-tail-latency.html https://blog.870919.xyz/posts/raft-consensus-tail-latency.html Fri, 14 Aug 2026 10:00:00 +0000 Analyzing p999 commit spikes in multi-AZ Raft clusters and batching ReadIndex heartbeats. Write Amplification vs. Read Tail Latency in LSM-Tree Storage Engines on Modern NVMe https://blog.870919.xyz/posts/lsm-tree-compaction-nvme.html https://blog.870919.xyz/posts/lsm-tree-compaction-nvme.html Fri, 03 Jul 2026 10:00:00 +0000 Comparing leveled compaction, sub-compaction parallelism, and key-value separation on NVMe drives.