BaselineProfileRule

@RequiresApi(value = 28)
public final class BaselineProfileRule implements TestRule


A TestRule that collects Baseline Profiles to be embedded in your APK.

These rules are used at install time to partially pre-compile your application code.

BaselineProfileRule is only supported on Android 13 (API 33) and above, or if using a rooted device, Android P (API 28) and above.

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

@Test
fun startup() = baselineProfileRule.collect(
packageName = "com.example.my.application.id"
) {
pressHome()
// This block defines the app's critical user journey. Here we are
// interested in optimizing for app startup, but you can also navigate
// and scroll through your most important UI.
startActivityAndWait()
}
}

Note that you can filter captured rules, for example, if you're generating rules for a library, and don't want to record profiles from outside that library:

    @Test
fun generateLibraryRules() = baselineProfileRule.collect(
// Target app is an integration test app which uses the library, but any
// app code isn't relevant to store in library's Baseline Profile
packageName = "com.example.testapp.id"
filterPredicate = {
// Only capture rules in the library's package, excluding test app code
// Rules are prefixed by tag characters, followed by JVM method signature,
// e.g. `HSPLcom/mylibrary/LibraryClass;-><init>()V`, where `L`
// signifies the start of the package/class, and '/' is divider instead of '.'
val libPackage = "com.mylibrary"
it.contains("^.*L${libPackage.replace(".", "/")}".toRegex())
},
) {
// ...
}

See the Baseline Profile Guide for more information on creating Baseline Profiles.

Summary

Public constructors

Public methods

@NonNull Statement
apply(@NonNull Statement base, @NonNull Description description)
final void
collect(
    @NonNull String packageName,
    int maxIterations,
    int stableIterations,
    String outputFilePrefix,
    boolean includeInStartupProfile,
    boolean strictStability,
    @NonNull Function1<@NonNull String, @NonNull Boolean> filterPredicate,
    @ExtensionFunctionType @NonNull Function1<@NonNull MacrobenchmarkScopeUnit> profileBlock
)

Collects baseline profiles for a critical user journey, while ensuring that the generated profiles are stable for a minimum of stableIterations.

Public constructors

BaselineProfileRule

Added in 1.1.0
public BaselineProfileRule()

Public methods

apply

Added in 1.1.0
public @NonNull Statement apply(@NonNull Statement base, @NonNull Description description)

collect

Added in 1.2.0
public final void collect(
    @NonNull String packageName,
    int maxIterations,
    int stableIterations,
    String outputFilePrefix,
    boolean includeInStartupProfile,
    boolean strictStability,
    @NonNull Function1<@NonNull String, @NonNull Boolean> filterPredicate,
    @ExtensionFunctionType @NonNull Function1<@NonNull MacrobenchmarkScopeUnit> profileBlock
)

Collects baseline profiles for a critical user journey, while ensuring that the generated profiles are stable for a minimum of stableIterations.

Parameters
@NonNull String packageName

Package name of the app for which profiles are to be generated.

int maxIterations

Maximum number of iterations to run when collecting profiles.

int stableIterations

Minimum number of iterations to observe as stable before assuming stability, and completing profile generation.

String outputFilePrefix

An optional file name prefix used when creating the output file with the contents of the human readable baseline profile. For example: outputFilePrefix-baseline-prof.txt

boolean includeInStartupProfile

determines whether the generated profile should be also used as a startup profile. A startup profile is utilized during the build process in order to determine which classes are needed in the primary dex to optimize the startup time. This flag should be used only for startup flows, such as main application startup pre and post login or other entry points of the app. Note that methods collected in a startup profiles are also utilized for baseline profiles.

boolean strictStability

Enforce if the generated profile was stable

@NonNull Function1<@NonNull String, @NonNull Boolean> filterPredicate

Function used to filter individual rules / lines of the baseline profile. By default, no filters are applied. Note that this works only when the target application's code is not obfuscated.

@ExtensionFunctionType @NonNull Function1<@NonNull MacrobenchmarkScopeUnit> profileBlock

defines the critical user journey.