`WOW_UI_EVENTS=<secs>` (`script/event_prof.rs`): per event, what one fire
costs across every handler it reaches, and which frame took the most of the
worst fire.
The gap it fills is a dispatcher. `WOW_UI_HANDLERS` keys on `(frame, script)`,
which is the right key for an `OnUpdate` and the wrong one for an `OnEvent`,
because every addon library registers *one* frame for *every* event it wants and
fans out in Lua. So the largest identifiable cost in grom's 2026-10-21 session,
eleven separate times, read as
[ui-handlers] 312.5 312.5 0.00 72522.3 AceEvent30Frame:OnEvent
— a true row that names a library's shared frame and no addon, no event and no
cause. `[sys-timing]` saw the same cost as `ui_quest::feed_quest` at 85.7 ms for
one run in 76, because every handler runs synchronously inside whichever system
fired, so the system holding the stack gets the bill.
Two conventions the report sticks to:
- `self` is nest-adjusted, in both columns. A handler's own time has any event it
fired taken back out (`event::fire` differences `event_prof::nested_ns` across
the call), or every event in a cascade reports the cascade and the row naming
the real cost is the one that looks innocent. `total` keeps it, which is what a
`[sys-timing]` span sees.
- A fire is one `fire_event`, however wide it fans out, because that is the unit
a dropped frame is measured in. `calls` is beside it for the width.
Measured on the player's own 92-addon interface (`tick_bench`'s new `[events]`
row, three fires per event from a settled start):
us/fire worst event
5068 14759 QUEST_DETAIL <- HCQuest.lua:139 took 14,097 us
764 1324 QUEST_LOG_UPDATE
662 1564 QUEST_FINISHED
Read `us/fire` against `worst` and that 14.8 ms is **one** fire of three: the
other two cost ~0.1 ms, so it is HCQuest building something once and keeping it,
not a cost paid per quest. With that read correctly, no quest event costs more
than ~1.5 ms recurring offline — so the bench does not reproduce the live 57-73
ms and says so, rather than offering a number that looks like an answer. Hence
the instrument, armed in `./measure.sh`.
Also adds `./measure.sh --frames`, which arms two meters that already existed and
have never been armed: `WOW_FRAME_PHASES=50` and `WOW_RENDER_MS=1`. A frame's
wall time is `max(main app, render app)` since bevy pipelines the render app onto
its own thread, so when the render app is the longer, `wall` climbs while `cpu`,
`main`, `gpu` and every per-system `worst` all read healthy — exactly what that
session's **161 ms frame in a second whose costliest system worst was 2.9 ms over
105 runs** looks like, and what 43 of its 64 spike-seconds look like. Its own
mode because both perturb what they measure.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SgstFWtn1RxEJ5kVrpgYwn
gromandClaude Opus 5
e269e4dbb4