Downright publishes a baseline benchmark rather than a universal speed promise. The corpus, date, target, and missing measurements stay beside every number.
Corpus and qualification
- Corpus: 120,825 characters / 4,885 lines
- Date: 2026-08-06
- Qualification: Baseline only. Not a cross-machine claim.
- Not measured: TextKit layout, scroll frames, IME input, live window frame time
Current baseline
| Measurement | p50 | p95 | Target |
|---|---|---|---|
| cmark parse | 12.827 ms | 13.309 ms | <250 ms |
| Full MarkdownParser.parse | 29.463 ms | 30.372 ms | Informational |
| AST dirty set, one-character edit | 0.030 ms | 0.031 ms | Informational |
| Text diff, external rewrite | 2.099 ms | 2.164 ms | Informational |
| Incremental decoration | 0.097 ms | 0.104 ms | <8 ms |
| Wholesale decoration | 103.722 ms | 171.493 ms | Informational |
| Source edit and paragraph map | 0.146 ms | 0.153 ms | <8 ms |
| End-to-end semantic convergence | 30.583 ms | 31.445 ms | <100 ms |
| Parse 100 KB | 12.078 ms | 12.395 ms | <250 ms |
| Syntax highlight, 10 KB Swift | 0.093 ms | 0.094 ms | Informational |
How to use the numbers
Use the benchmark to detect regressions in the same corpus and build path. Do not treat it as a promise about every Mac, document, display refresh rate, or window size. The app's release checks keep the methodology and limitations visible.