Compose performance
Core principle
Measure one user-visible transition, identify the runtime axis that causes the work, then apply the smallest correction at the phase or boundary where that axis begins.
Procedure
- Reproduce one concrete transition and capture the observable evidence: recomposition counts, compiler reports, profiler data, or a clear trace.
- Classify the primary axis: parameter stability and skipping, State read phase, or snapshot state written back into an earlier phase.
- Check for a false lead: a real data change, a correctness defect, or an unchanged lazy item that is expected to recompose.
- Read the corresponding focused reference before proposing a change.
- For review work, pair every finding with the smallest evidence-supported
repair. For a false stability promise, explicitly say to replace mutable
non-snapshot properties with immutable data or snapshot-observable state,
verify that contract, and only then decide whether an annotation remains
needed. For a phase problem, name the layout or draw consumer where the
changing read or calculation should move. A cross-phase write proves
invalidation or an extra pass; do not claim oscillation or an infinite loop
unless evidence shows values repeatedly changing. Do not stop at diagnosis.
When only source code is available, separate the proven feedback path from
its unmeasured runtime cost. Give a conditional repair direction based on
the intended measurement boundary; do not prescribe a callback swap,
equality guard, or content-layout rewrite as a performance fix without
evidence that it changes the observed problem. For an
Intheld inmutableStateOfwith the default structural equality policy, an unchanged value already avoids invalidation. - Change one axis at a time and re-measure the same transition.
- Finish when the evidence improves at the observed boundary without hiding state changes, caching stale values, or moving work to a less correct owner.
Topic router
| Signal | Read |
|---|---|
| Cause is unknown, or several axes may interact | Diagnosis |
classes.txt, composables.txt, strong skipping, unstable parameters, or collection stability | Stability |
| Scroll, animation, gesture, layout, or draw State read at frame rate; measured state fed back into composition | Deferred reads |
| A composable only reads composition locals or accessor-style values | Composition contracts |
| State ownership or effect lifecycle is the root cause | Compose state and effects |
