PerfettoTraceRule

@ExperimentalPerfettoCaptureApi
class PerfettoTraceRule : TestRule

Add this rule to record a Perfetto trace for each test on Android Lollipop (API 21)+ devices.

@RunWith(AndroidJUnit4::class)
class PerfettoOverheadBenchmark {
    // traces all tests in file
    @get:Rule
    val perfettoRule = PerfettoTraceRule()

    @Test
    fun test() {}
}

Captured traces can be observed through any of:

• Android Studio trace linking under Benchmark in test output tab

• The optional traceCallback parameter

• Android Gradle defining and pulling the file via additionalTestOutputDir.

When invoked via Gradle, files will be copied to host path like the following:

out/build/outputs/connected_android_test_additional_output/debugAndroidTest/connected/<deviceName>/androidx.mypackage.TestClass_testMethod.perfetto-trace

You can additionally check logcat for messages tagged "PerfettoCapture:" for the path of each perfetto trace.

> adb pull /storage/emulated/0/Android/data/mypackage.test/files/PerfettoCaptureTest.trace

Reentrant Perfetto trace capture is not supported, so this API may not be combined with BenchmarkRule, MacrobenchmarkRule, or PerfettoTrace.record.

Summary

PerfettoTraceRule(
    enableAppTagTracing: Boolean = true,
    enableUserspaceTracing: Boolean = false,
    traceCallback: ((PerfettoTrace) -> Unit)? = null
)

open fun apply(base: Statement, description: Description): Statement

val enableAppTagTracing: Boolean

val enableUserspaceTracing: Boolean

val traceCallback: ((PerfettoTrace) -> Unit)?