About
Notes I keep for myself, mostly while debugging something at work and discovering that the thing I believed about a tool was wrong.
The recurring theme here is that our instruments lie by omission. A flame
graph does not show blocked time. strace -c does not show userspace.
Load average cannot tell saturation from parallelism. None of these are bugs
— they are just measuring something narrower than what we assume, and the
gap is where the wasted days come from.
Corrections
If something here is wrong I would rather know. The pages are static and edited in place; substantive changes get a note at the bottom of the post.
Colophon
Static HTML, no build step, no JavaScript. System fonts. The flame graph on the index is hand-drawn SVG from a real profile, not a screenshot.