https://jasper-aa64.github.io/zh/tags/perf/Recent content in Perf on JasperHugozh-CNThu, 22 Oct 2026 00:00:00 +0000https://jasper-aa64.github.io/zh/posts/low-latency-perf-profiling/Thu, 22 Oct 2026 00:00:00 +0000https://jasper-aa64.github.io/zh/posts/low-latency-perf-profiling/先用 stat 看总账，再用 record 和 report 找到占 98% 样本的函数，最后用 annotate 看到样本全落在加法后面一条指令上：那是一条一环扣一环的加法链，拆成四路就快了 3.3 倍。拿不到硬件计数器时，cpu-clock 采样照样能用；报告里只剩地址，先查符号表和程序所在的路径。