kitesurf · bench

Backend comparison — median wall time

One grouped bar per page, one bar per backend. Bar height = median wall time from the orchestrator's performance.now() span. Hover a bar for median/p95/p99. Missing or all-errored cells render as a thin grey stub.

Backend comparison — median backend CPU time

Server-side CPU per call. Kitesurf reports $workers.cpuTimeMs from Workers Observability; container reports Node-side CPU via timing headers. Browser-run doesn't expose a CPU counter — bars render as a grey stub.

Backend comparison — median memory

Per-page memory at end of render. The two backends report different things — bars are directionally comparable, not strictly apples-to-apples.

• kitesurf: kitesurf_core wasm linear memory size (WebAssembly.Memory.buffer.byteLength via Kitesurf.getMemoryStats). The wasm heap covers everything the renderer uses — DOM, parley, vello, stylo, image decode, screenshot raster — but it's a coarse high-water proxy: Rust's dlmalloc grows in chunks and doesn't release back to the OS, so the reading reflects peak demand rather than bytes-in-use. Per-render: each navigate gets a fresh isolate.
• container: per-page memory from CDP Runtime.getHeapUsage (the same RPC DevTools' Memory panel uses), captured right after the page's load pipeline finishes — before V8's idle-time GC compacts the arenas. The value is totalSize (V8 heap arena) + embedderHeapUsedSize (Blink's native state: DOM, layout, image cache, style data) + backingStorageSize (ArrayBuffer / typed-array backings), matching DevTools' "Total JS heap size" for a live page. Doesn't cover GPU buffers or other renderer state outside Blink's embedder heap.

In short: kitesurf overcounts (high-water peak across the whole renderer); container undercounts (JS heap only). The truth for either backend lives somewhere between the two columns.

Latest run · per-metric tables

Same layout as npm run bench: per endpoint, tables for wall, cpu, mem. Each backend's median/p95/p99 side by side. ks = kitesurf, br = browser-run, ct = container. — = backend doesn't report this metric. err = every recorded run for that combination errored. See the memory chart's caption above for the per-backend metric semantics.

History

Latest report (markdown)

latest.md latest.json history.json badge.svg

# kitesurf bench report — 2026-07-11

commit: `15ac2dc` · backends: kitesurf, container · endpoints: screenshot, html · runs/combo: 5 (+ 2 warmup)
target: https://kitesurf-bench.rendering.cfdata.org

## Summary (median wall time)

| Page | kitesurf/screenshot | kitesurf/html | container/screenshot | container/html |
|---|--:|--:|--:|--:|
| Example Domain | 847ms | 814ms | 405ms | 232ms |
| Hacker News | 1178ms | 1023ms | 855ms | 619ms |
| Cloudflare Developer Docs | 3340ms | 3318ms | 858ms | 725ms |
| The Cloudflare Blog | 1644ms | 1653ms | 1031ms | 823ms |
| Wikipedia Portal | 1195ms | 1488ms | 884ms | 589ms |
| Der Spiegel | 1626ms | 1651ms | 1804ms | 2011ms |
| El Mundo | 5273ms | 2085ms | 1633ms | 1216ms |
| TodoMVC · JavaScript ES6 | 844ms | 809ms | 541ms | 310ms |
| TodoMVC · React | 1476ms | 850ms | 527ms | 335ms |
| TodoMVC · Vue | 1081ms | 855ms | 508ms | 403ms |
| TodoMVC · Angular | 986ms | 898ms | 627ms | 407ms |
| TodoMVC · Preact | 816ms | 792ms | 549ms | 285ms |

Notes:

- Values are run medians across recorded runs. p95 and min/max are in the JSON.
- Backends are dispatched from inside the `kitesurf-bench` worker via RPC bindings: `env.KITESURF.fetch(/screenshot|/html)` for kitesurf (service binding to the engine), `env.BROWSER.quickAction('screenshot'|'content', …)` for browser-run (Browser Rendering RPC), and `env.CONTAINER_HOST.fetch(…)` for container (sibling worker fronting its container backend). Wall time is the orchestrator's `performance.now()` span; `backendWallMs` / `backendCpuMs` in the JSON come from Workers Observability (kitesurf) or container-side timing headers (container). None of the measurement paths traverse the public internet.
- A cell shows `—` when every recorded run for that combination errored. See `rows` in the JSON for individual failure messages.

bundle built 2026-07-11T17:46:18.286Z