https://docs.rs/mobench

mobench

Mobile benchmarking CLI for Rust - Run benchmarks on real Android and iOS devices.

The mobench CLI is the easiest way to benchmark your Rust code on mobile devices. It handles everything from project setup to building mobile apps to running tests on real devices via BrowserStack.

Installation

cargo install mobench

Or use as a Cargo subcommand:

cargo install mobench
cargo mobench --help

Quick Start

1. Initialize Your Project

# Create mobile benchmarking setup for Android
cargo mobench init --target android

# Or for iOS
cargo mobench init --target ios

# Or for both platforms
cargo mobench init --target both

This creates:

• bench-mobile/ - FFI wrapper crate with UniFFI bindings
• android/ or ios/ - Platform-specific app projects (generated to output directory)
• bench-config.toml - Run configuration file
• mobench.toml - Project configuration file (when using init)
• benches/example.rs - Example benchmarks (with --examples)

2. Write Benchmarks

// benches/my_benchmarks.rs
use mobench_sdk::benchmark;

#[benchmark]
fn fibonacci_30() {
    let result = fibonacci(30);
    std::hint::black_box(result);
}

fn fibonacci(n: u32) -> u64 {
    match n {
        0 => 0,
        1 => 1,
        _ => fibonacci(n - 1) + fibonacci(n - 2),
    }
}

3. Build for Mobile

# Build Android APK
cargo mobench build --target android

# Build iOS app
cargo mobench build --target ios

4. Run Benchmarks

Local device workflow (builds artifacts and writes the run spec; launch the app manually):

cargo mobench run --target android --function fibonacci_30 --iterations 50

On real devices via BrowserStack:

export BROWSERSTACK_USERNAME=your_username
export BROWSERSTACK_ACCESS_KEY=your_access_key

cargo mobench run \
  --target android \
  --function fibonacci_30 \
  --devices "Google Pixel 7-13.0" \
  --iterations 100 \
  --warmup 10 \
  --release

Note: Always use the --release flag for BrowserStack runs. Debug builds are significantly larger (~544MB vs ~133MB for release) and may cause upload timeouts.

Commands

init - Initialize Project

Create mobile benchmarking infrastructure:

cargo mobench init [OPTIONS]

Options:

• --target <android|ios|both> - Target platform (default: android)
• --output <FILE> - Config file path (default: bench-config.toml)

Example:

cargo mobench init --target both --output my-bench.toml

build - Build Mobile Apps

Cross-compile and package for mobile platforms:

cargo mobench build --target <android|ios> [OPTIONS]

Options:

• --target <android|ios> - Platform to build for (required)
• --release - Build in release mode (default: debug)
• --output-dir <DIR> - Output directory for mobile artifacts (default: target/mobench/)
• --crate-path <PATH> - Path to the benchmark crate (default: auto-detect)
• --dry-run - Print what would be done without making changes
• --verbose / -v - Print verbose output including all commands

Examples:

# Build Android APK in release mode
cargo mobench build --target android --release

# Build iOS xcframework
cargo mobench build --target ios

# Preview build without making changes
cargo mobench build --target android --dry-run

# Build with verbose output
cargo mobench build --target ios --verbose

# Build to custom output directory
cargo mobench build --target android --output-dir ./my-output

Outputs:

• Android: target/mobench/android/app/build/outputs/apk/debug/app-debug.apk
• iOS: target/mobench/ios/sample_fns.xcframework

run - Run Benchmarks

Execute benchmarks on devices:

cargo mobench run --target <android|ios> --function <NAME> [OPTIONS]

Options:

• --target <android|ios> - Platform (required)
• --function <NAME> - Benchmark function name (required)
• --iterations <N> - Number of iterations (default: 100)
• --warmup <N> - Warmup iterations (default: 10)
• --devices <LIST> - Comma-separated device list for BrowserStack
• --local-only - Skip mobile builds (no device run)
• --config <FILE> - Load run spec from config file
• --ios-app <FILE> - iOS .ipa or zipped .app for BrowserStack
• --ios-test-suite <FILE> - iOS XCUITest runner (.zip or .ipa)
• --output <FILE> - Save results to JSON file (default: run-summary.json)
• --summary-csv - Write CSV summary alongside JSON/Markdown
• --fetch - Fetch BrowserStack results after completion

Outputs:

• JSON summary (default: run-summary.json)
• Markdown summary (same base name, .md)
• CSV summary (same base name, .csv, when --summary-csv is set)

Examples:

# Run locally (no BrowserStack devices specified)
cargo mobench run --target android --function fibonacci_30

# Run on BrowserStack devices (use --release for smaller APK)
cargo mobench run \
  --target android \
  --function sha256_hash \
  --devices "Google Pixel 7-13.0,Samsung Galaxy S23-13.0" \
  --iterations 50 \
  --release \
  --output results.json

# Run on iOS with auto-fetch (use --release for smaller artifacts)
cargo mobench run \
  --target ios \
  --function json_parse \
  --devices "iPhone 14-16,iPhone 15-17" \
  --release \
  --fetch

package-ipa - Package iOS IPA

Create a signed IPA for BrowserStack:

cargo mobench package-ipa [OPTIONS]

Options:

• --scheme <NAME> - Xcode scheme (default: BenchRunner)
• --method <adhoc|development> - Signing method (default: adhoc)

Example:

cargo mobench package-ipa --method adhoc

Output: target/mobench/ios/BenchRunner.ipa

package-xcuitest - Package XCUITest Runner

Create the XCUITest runner package required for BrowserStack iOS testing:

cargo mobench package-xcuitest [OPTIONS]

Options:

• --scheme <NAME> - Xcode scheme for UI tests (default: BenchRunnerUITests)

Example:

cargo mobench package-xcuitest

Output: target/mobench/ios/BenchRunnerUITests.zip

This command builds the XCUITest target and packages it into the zip format that BrowserStack expects for iOS test automation.

plan - Generate Device Matrix

Create a template device matrix file:

cargo mobench plan [--output <FILE>]

Example:

cargo mobench plan --output devices.yaml

Output: device-matrix.yaml

devices:
  - name: Google Pixel 7-13.0
    os: android
    os_version: "13.0"
    tags: [default, pixel]
  - name: iPhone 14-16
    os: ios
    os_version: "16"
    tags: [default, iphone]

list - List Benchmarks

Show benchmarks discovered via #[benchmark]:

cargo mobench list

fetch - Fetch Results

Download BrowserStack build artifacts:

cargo mobench fetch --target <android|ios> --build-id <ID> [OPTIONS]

Options:

• --target <android|ios> - Platform (required)
• --build-id <ID> - BrowserStack build ID (required)
• --output-dir <DIR> - Download directory (default: target/browserstack)

Example:

cargo mobench fetch \
  --target android \
  --build-id abc123def456 \
  --output-dir ./results

compare - Compare Summaries

Compare two JSON run summaries and emit a Markdown report:

cargo mobench compare \
  --baseline results-v1.json \
  --candidate results-v2.json \
  --output comparison.md

Configuration

Project Configuration (mobench.toml)

mobench automatically loads mobench.toml from the current directory or any parent directory:

[project]
# Name of the benchmark crate
crate = "bench-mobile"

# Rust library name (typically crate name with hyphens replaced by underscores)
library_name = "bench_mobile"

# Output directory for build artifacts (default: target/mobench/)
# output_dir = "target/mobench"

[android]
# Android package name
package = "com.example.bench"

# Minimum Android SDK version (default: 24)
min_sdk = 24

# Target Android SDK version (default: 34)
target_sdk = 34

[ios]
# iOS bundle identifier
bundle_id = "com.example.bench"

# iOS deployment target version (default: 15.0)
deployment_target = "15.0"

# Development team ID for code signing (optional)
# team_id = "YOUR_TEAM_ID"

[benchmarks]
# Default benchmark function to run
default_function = "my_crate::my_benchmark"

# Default number of benchmark iterations
default_iterations = 100

# Default number of warmup iterations
default_warmup = 10

CLI flags always override config file values when provided.

Run Config File Format (bench-config.toml)

For BrowserStack runs, you can also use a separate run configuration:

target = "android"
function = "sample_fns::fibonacci"
iterations = 100
warmup = 10
device_matrix = "device-matrix.yaml"
device_tags = ["default"] # optional; filter devices by tag

[browserstack]
app_automate_username = "${BROWSERSTACK_USERNAME}"
app_automate_access_key = "${BROWSERSTACK_ACCESS_KEY}"
project = "my-project-benchmarks"

[ios_xcuitest]
app = "target/mobench/ios/BenchRunner.ipa"
test_suite = "target/mobench/ios/BenchRunnerUITests.zip"

Device Matrix Format (device-matrix.yaml)

devices:
  - name: "Google Pixel 7-13.0"
    os: "android"
    os_version: "13.0"
    tags: ["default", "pixel"]
  - name: "iPhone 14-16"
    os: "ios"
    os_version: "16"
    tags: ["default", "iphone"]

Environment Variables

BrowserStack credentials can be provided via:

1. Environment variables (recommended):

   export BROWSERSTACK_USERNAME=your_username
   export BROWSERSTACK_ACCESS_KEY=your_access_key
   

2. .env.local file:

   BROWSERSTACK_USERNAME=your_username
   BROWSERSTACK_ACCESS_KEY=your_access_key
   

3. Config file with variable expansion:

   [browserstack]
   username = "${BROWSERSTACK_USERNAME}"
   access_key = "${BROWSERSTACK_ACCESS_KEY}"
   

Requirements

For Android

• Android NDK - Set ANDROID_NDK_HOME environment variable
• cargo-ndk - Install with cargo install cargo-ndk
• Android SDK - API level 24+ required
• Gradle - For building APKs (bundled with Android project)

For iOS

• macOS with Xcode installed
• Xcode Command Line Tools - xcode-select --install
• Rust iOS targets:

  rustup target add aarch64-apple-ios
  rustup target add aarch64-apple-ios-sim
  

• XcodeGen - Install with brew install xcodegen

For BrowserStack

• BrowserStack App Automate account - Sign up
• Credentials - Username and access key from account settings

Examples

Benchmark Crypto Operations

# Initialize
cargo mobench init --target android

# Add benchmark
cat > benches/crypto.rs <<'EOF'
use mobench_sdk::benchmark;
use sha2::{Sha256, Digest};

#[benchmark]
fn sha256_1kb() {
    let data = vec![0u8; 1024];
    let hash = Sha256::digest(&data);
    std::hint::black_box(hash);
}
EOF

# Build
cargo mobench build --target android --release

# Run on multiple devices (use --release for BrowserStack)
cargo mobench run \
  --target android \
  --function sha256_1kb \
  --devices "Google Pixel 7-13.0,Samsung Galaxy S23-13.0,OnePlus 11-13.0" \
  --iterations 200 \
  --release \
  --output crypto-results.json

Compare iOS Performance

# Run same benchmark on different iOS versions (use --release for BrowserStack)
cargo mobench run \
  --target ios \
  --function json_parse \
  --devices "iPhone 13-15,iPhone 14-16,iPhone 15-17" \
  --iterations 100 \
  --release \
  --fetch \
  --output ios-comparison.json

CI Integration

# .github/workflows/mobile-bench.yml
name: Mobile Benchmarks

on: [push]

jobs:
  benchmark:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Install mobench
        run: cargo install mobench

      - name: Setup Android NDK
        uses: nttld/setup-ndk@v1
        with:
          ndk-version: r25c

      - name: Build
        run: cargo mobench build --target android --release

      - name: Run benchmarks
        env:
          BROWSERSTACK_USERNAME: ${{ secrets.BROWSERSTACK_USERNAME }}
          BROWSERSTACK_ACCESS_KEY: ${{ secrets.BROWSERSTACK_ACCESS_KEY }}
        run: |
          cargo mobench run \
            --target android \
            --function my_benchmark \
            --devices "Google Pixel 7-13.0" \
            --iterations 50 \
            --release \
            --output results.json \
            --fetch

      - name: Upload results
        uses: actions/upload-artifact@v3
        with:
          name: benchmark-results
          path: results.json

Workflow

┌─────────────────────┐
│ 1. cargo mobench    │
│    init             │
└──────────┬──────────┘
           │
           ↓
┌─────────────────────┐
│ 2. Write benchmarks │
│    with #[benchmark]│
└──────────┬──────────┘
           │
           ↓
┌─────────────────────┐
│ 3. cargo mobench    │
│    build            │
└──────────┬──────────┘
           │
           ↓
┌─────────────────────┐
│ 4. cargo mobench    │
│    run              │
└──────────┬──────────┘
           │
      ┌────┴────┐
      ↓         ↓
┌──────────┐ ┌──────────────┐
│  Local   │ │ BrowserStack │
│ Emulator │ │ Real Devices │
└──────────┘ └──────────────┘

Troubleshooting

Android NDK not found

export ANDROID_NDK_HOME=/path/to/ndk

Or install via Android Studio: Tools → SDK Manager → SDK Tools → NDK

iOS code signing issues

For BrowserStack testing, use ad-hoc signing:

cargo mobench package-ipa --method adhoc

BrowserStack authentication failed

Verify credentials:

echo $BROWSERSTACK_USERNAME
echo $BROWSERSTACK_ACCESS_KEY

Or check .env.local file exists and contains valid credentials.

Benchmark function not found

Ensure:

1. Function has #[benchmark] attribute
2. Function is compiled into the mobile binary
3. Function name matches exactly (case-sensitive)

Part of mobench

This CLI is part of the mobench ecosystem:

• mobench - This crate (CLI tool)
• mobench-sdk - Core SDK with timing harness, build automation, and codegen
• mobench-macros - #[benchmark] proc macro

See Also

• mobench-sdk Documentation for programmatic API
• BrowserStack App Automate for device cloud
• UniFFI Documentation for FFI details

License

Licensed under the MIT License. See LICENSE.md for details.

Copyright (c) 2026 World Foundation