| name | perf-gate |
| description | Performance gate for gfx/shader work. Capture baseline, change, capture after, report delta. Use before any non-trivial rendering change. |
| when_to_use | Performance-sensitive rendering work, esp. shader changes. Skip non-rendering, trivial, perf-not-concern. |
| triggers | {"files":["src/shader.wgsl","src/main.rs","src/rendering.rs","src/ui.rs","assets/stack.stk"],"keywords":["performance","fps","slow","profile","optimize","shadow cost","displacement cost","lighting cost"]} |
| auto_suggest | true |
| tags | ["skill","material","shading","graphics","code","pipeline"] |
Performance Gate
Contract
Every rendering/shader task:
- Capture before baseline
- Implement change
- Capture after baseline
- Report delta
Done requires: app run check + compile check + screenshot artifact + perf artifact.
Pre-work
cargo check
cargo run -- --perf
python skills/perf-gate/scripts/update_baseline.py
update_baseline.py writes profiling/perf_baseline.csv — two rows: latest (newest avg), previous (prior avg). Screenshot → screenshots/frame-6000-*.png.
Custom stop frame (early-frame regressions): cargo run -- --stop-frame=1200.
Decision rule
Read profiling/perf_baseline.csv, call out: full_ms, lighting_ms, shadow_ms, displacement_ms, avg_step_ms. Verify newest screenshot valid + clean exit. Pick dominant cost first (highest ms).
During optimization
- Narrow scope: one bottleneck at a time
- After each meaningful change: compile + perf run + baseline update
- Report delta vs
previous (ms + %)
Done criteria
- Latest improves target without major regression elsewhere
perf_baseline.csv updated, attached in summary- Before/after screenshot paths in summary
