WeakAuras
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Event handling optimization
🕑 Added 2019-05-29 05:35:21 +0000 UTCHi, Buds here to describe a optimization in the event handling for the next release.
How events from triggers are handled in WeakAuras
In WeakAuras, Triggers (generic or custom) are functions that are executed after an event is executed.
Each trigger has to register a list of events it listens to, this is centralized in a single event dispatcher in charge of calling all trigger functions.
What was the problem?
While investigating a performance issue only happening while in a raid group, the profiling function showed that the trigger "Action Usable" was consuming 85% of its (not global) CPU time on the event "UNIT_POWER_FREQUENT".
This trigger is pretty simple, but the way the event was handled didn't scale very well with group size, it was called for each unit that was gaining or losing power instead of just the player.
Until now, all events were registered with the function RegisterEvent which doesn't filter by unit, so this had to change.
RegisterUnitEvent to the rescue!
Starting with WeakAuras 2.12.4-beta3 or newer, generic triggers now use RegisterUnitEvent for UNIT_* events with a valid UnitId instead.
This will drastically improve performance of "Power", "Health", "Cast", "Action Usable" and other triggers relying on UNIT_* events.
If you write custom code, custom triggers also benefit from this and the "Event(s)" field has been extended to support unit filters. E.g.:
- UNIT_TARGET:boss1:boss2:boss3:boss4:boss5
- UNIT_SPELLCAST_SUCCEEDED:player:target
COMBAT_LOG_EVENT_UNFILTERED Sub-Event Filters
The "Combat Log" generic trigger already supported sub event filtering at the dispatcher level but we also added that functionnality for custom triggers that are using COMBAT_LOG_EVENT_UNFILTERED. E.g.;
- COMBAT_LOG_EVENT_UNFILTERED:SPELL_CAST_START
- CLEU:SPELL_CAST_START:SPELL_AURA_APPLIED
In addition, you can now also use the "CLEU" shorthand instead of "COMBAT_LOG_EVENT_UNFILTERED" in the "Events(s)" field.
In conclusion, over time WeakAuras has grown a lot and is now a major tool for many World of Warcraft players, we deeply care about performance and will continue to improve it over time.
