designbench

designbench is a Go CLI that runs cross-platform UI render benchmarks for Kotlin Multiplatform apps. It orchestrates Android Compose and iOS SwiftUI targets, records render/system metrics, and emits JSON reports for CI.

Install

Homebrew (macOS/Linux):

brew tap tahatesser/designbench https://github.com/tahatesser/designbench.git
brew install designbench          # installs the latest tagged release
# or install straight from `main`
brew install designbench --HEAD

Core Commands

Command	Purpose	Key flags
designbench preflight	PASS/WARN/FAIL checklist for tooling (adb/xcodebuild/xcrun), project manifests, and attached devices.	(none – everything auto-detected)
designbench android	Runs Compose benchmark via adb shell am start -W, captures launch + CPU/memory metrics, saves JSON.	--view, --component
designbench ios	Runs SwiftUI benchmark using xcrun simctl launch, captures render + CPU/memory metrics, saves JSON.	--view, --component

--view labels the UI under test, while --component controls the report filename token. Package/activity and bundle identifiers are inferred from AndroidManifest.xml and Info.plist when you run commands from the project root.

Typical Flow

1. designbench preflight – confirm tools, manifests, and devices are ready.
2. Build and install the KMP app on Android (via Gradle) and iOS (via Xcode).
3. designbench android --view ScreenX --component ScreenX
4. designbench ios --view ScreenX --component ScreenX

Both platform commands write JSON to designbench-reports/ (override with --output) and print a terminal summary that includes launch timings, CPU%, CPU time, memory usage, and device metadata.

Reports

Each report stores:

• component label and CLI invocation
• render metrics (FirstFrameMs, TotalTimeMs, RenderTimeMs)
• system metrics (memory MB, CPU %, CPU time)
• timestamp and device details (model/OS/resolution or simulator name/runtime)

The data is CI-friendly and can be diffed against baselines for regressions.

Example Report

{
  "component": "ScreenX",
  "cliCommand": "designbench android --view ScreenX --component ScreenX --output reports/screenx-android.json",
  "android": {
    "component": "ScreenX",
    "package": "com.example.app",
    "activity": ".BenchmarkActivity",
    "firstFrameMs": 8.1,
    "totalTimeMs": 12.4,
    "waitTimeMs": 14.0,
    "memoryMB": 42.0,
    "cpuPercent": 9.8,
    "cpuTimeMs": 1500,
    "device": {
      "id": "FA6AX0301234",
      "platform": "android",
      "model": "Pixel 7",
      "osVersion": "14",
      "resolution": "1080x2400"
    },
    "timestamp": "2024-05-01T12:34:56Z"
  }
}

CI Support

.github/workflows/android-ci.yml defines a GitHub Actions job that:

1. Runs go test ./....
2. Builds the CLI.
3. Uses scripts/mock-adb.sh to run a smoke designbench android invocation without physical hardware, writing JSON via --output for CI artifacts.

Use it as a template—swap the mock bridge for a real device lab when available.