Limits of the evidence
Every router measurement on this site was taken on one device, an RB5009UG+S+, under that router’s own traffic and the few events provoked on purpose. They were not taken on one day: the oldest, the cost of an SSH connect, dates from 2026-08-26 on RouterOS 7.24.1, and the others from 2026-09-11 on, on 7.24.2 and later 7.24.4; Tested on dates each one. The virtual lab’s CHR adds correctness, not cost: it is not a board, and none of its durations or CPU figures measures a router. What follows is what these measurements do not tell you, kept here rather than left for a reader to discover by being wrong.
Histogram limits
Section titled “Histogram limits”The histogram mikroscope_ (integer busy ticks per sample and core, which keeps
timing jitter out of the bucket choice) recovers time above a threshold to one sample. It cannot recover contiguity: a 2 s plateau at 30 % and twenty
scattered 100 ms spikes at 30 % look identical in it.
That is what mikroscope_ is for —
the length of each run of consecutive samples at or above the threshold,
observed when the run ends, with the run still in progress in
…_run_open_seconds.
The trailing-window gauges (window="1s"|"10s"|"60s", stat="max"|"min"|"p95")
show the peak whatever your scrape interval is, because the collector computes them
over the agent’s own sample timestamps rather than over your scrape times. To see the shape of a transient
rather than its envelope, record it, or let a trigger capture it.
Sampler timing
Section titled “Sampler timing”How late the sampler woke after its ticker and how long the read took are
mikroscope_ and mikroscope_, with
the interval actually achieved in mikroscope_. If you
suspect the sampler rather than the router, those three are where to look
first.
The agent keeps 60 s by default. A collector outage shorter than that is
backfilled on reconnect through since=<seq>; a longer one is reported as a gap
of known length — a marker in a recording, a counter on the collector. A chart
with a hole in it is a chart telling the truth.