Baseline Profiles and App Performance

plugins {
    id("com.android.application")
    id("androidx.baselineprofile")
}
dependencies {
    implementation("androidx.profileinstaller:profileinstaller:<version>")   // installs profiles for sideloaded/non-Play installs
    "baselineProfile"(project(":baselineprofile"))
}

@RunWith(AndroidJUnit4::class)
@LargeTest
class BaselineProfileGenerator {
    @get:Rule val rule = BaselineProfileRule()

    @Test
    fun generate() = rule.collect(
        packageName = "com.example.app",
        includeInStartupProfile = true,          // also generate a startup profile for DEX layout
    ) {
        // 1. Startup
        pressHome()
        startActivityAndWait()

        // 2. Most important journey: scroll the feed, open an item
        val feed = device.findObject(By.res("feed_list"))
        feed.setGestureMargin(device.displayWidth / 5)
        feed.fling(Direction.DOWN)
        device.waitForIdle()
        device.findObject(By.res("feed_item_0"))?.click()
        device.waitForIdle()
    }
}

Scaffold(modifier = Modifier.semantics { testTagsAsResourceId = true }) { /* ... */ }
LazyColumn(Modifier.testTag("feed_list")) { /* ... */ }

./gradlew :app:generateBaselineProfile
# Writes the profile into the app module's source set; commit it to version control.

@Test fun startupNoProfile() = startup(CompilationMode.None())
@Test fun startupWithProfile() = startup(CompilationMode.Partial(BaselineProfileMode.Require))

private fun startup(mode: CompilationMode) = benchmarkRule.measureRepeated(
    packageName = "com.example.app",
    metrics = listOf(StartupTimingMetric()),
    compilationMode = mode,
    startupMode = StartupMode.COLD,
    iterations = 10,
) { pressHome(); startActivityAndWait() }