ops/s alone can't tell you whether a device is saturated — it reads low on a
few large IOs that pin the disk at 100% busy, and high on many small cached
ones. sample io_ticks (diskstats field 13) instead: its delta over the
interval is device busy time, i.e. iostat's %util. take the busiest single
device rather than the sum, since summing across devices exceeds 100% on a
multi-disk node and means nothing as a saturation percentage.
divide by the real elapsed gap rather than the nominal interval — a loaded or
throttled runner drifts well past 1.0s and would otherwise report >100%.
emit a downsampled series (cpu/mem/disk, 0-100 ints) alongside the existing
summary, mean-bucketed to 180 points so a 40min job costs the same few KB as
a 40s one. the report inlines every profile into one self-contained html
file, so an unbounded 1Hz series would dominate its size. mean, not every Nth
sample: a spike that survives decimation by luck is misleading.
the report renders the series as svg sparklines over each gantt bar, in two
states off the same markup (3px strip when collapsed, full height when
expanded) via preserveAspectRatio=none. profiles predating the series field
degrade to table-only, no overlay.
tests/ci 62/62.
ethernet