Measurement-driven systems performance, for people who read the disassembly.https://lowlat.msen-ushttps://lowlat.ms/posts/cache-line-visualizerhttps://lowlat.ms/posts/cache-line-visualizerAn interactive that lets you feel cache-line behavior: array-of-structs vs struct-of-arrays, false sharing in action, 64-byte alignment, the padding trick — the visceral version of things every systems engineer has memorized.Sat, 11 Apr 2026 00:00:00 GMTcachefalse-sharingvisualizationinteractivemechanical-sympathyJonathanhttps://lowlat.ms/posts/io-uring-vs-epoll-vs-blocking-readhttps://lowlat.ms/posts/io-uring-vs-epoll-vs-blocking-readAt what request rate, batch size, and connection count does io_uring beat epoll for a real network read workload on Linux 6.18 LTS — and does it hold across kernels, NUMA topologies, and SQPOLL modes?Sat, 11 Apr 2026 00:00:00 GMTio_uringepolllinuxbenchmarknetworkingsyscallsJonathanhttps://lowlat.ms/posts/hnsw-cache-pressurehttps://lowlat.ms/posts/hnsw-cache-pressureWhen you serve queries against an HNSW index that exceeds your buffer cache, where does the cache pressure actually fall? Which levels miss, how often, and which graph traversal patterns are pathological?Sat, 11 Apr 2026 00:00:00 GMThnswvector-searchcacheperf-c2cragbenchmarkJonathan