How blogging forces a deeper understanding of hard problems – and increases the impact of your solutions| writethatblog.substack.com
Back in 2018 I wrote about how to apply Brendan Gregg’s FlameGraphs for visualizing SQL plan execution time 1, using the plan node-level context and timing data that some database engines provide. This approach is not designed to replace the traditional plan display methods that are packed with lots of additional metrics and details. Nevertheless, in case of large execution plans, SQL plan flamegraphs give you a quick overview of both the plan structure, tables and operations involved and w...| tanelpoder.com
TL;DR: Some Linux distros and even different kernel versions within a distro have disabled IRQ time accounting. In such case, your monitoring tools will report zero time spent in hardware interrupt handlers (shown as %hi, %irq, hiq, etc). It’s easy to check how your kernel is behaving by looking at /proc/stat and you can still measure interrupt CPU usage using perf and a little creativity. Index Index Problem Explanation Kernel configuration options Measuring IRQ time with perf Different di...| tanelpoder.com