You can quickly start using the Microbenchmark library by adding changes to your application code. For the proper project setup, follow the Full setup section, which requires more complicated changes to your codebase.
Quickstart
This section provides a quick guide to try out benchmarking and run one-off measurements without requiring you to move code into modules. For accurate performance results, these steps involve disabling debugging in your application, so you should keep this in local working copy without committing the changes to your source control system.
To quickly perform one-off benchmarking, do the following:
Add the library to your module’s
build.gradle
file:project_root/module_dir/build.gradle
Groovy
dependencies { androidTestImplementation 'androidx.benchmark:benchmark-junit4:1.1.1' }
Kotlin
dependencies { androidTestImplementation("androidx.benchmark:benchmark-junit4:1.1.1") }
To disable debugging in the test manifest, update your
<application>
element to force-disable debugging temporarily:project_root/module_dir/src/androidTest/AndroidManifest.xml
<!-- Important: disable debuggable for accurate performance results --> <application android:debuggable="false" tools:ignore="HardcodedDebugMode" tools:replace="android:debuggable"/>
To add your benchmark, add an instance of
BenchmarkRule
in a test file in theandroidTest
directory. For more information on writing benchmarks, see Create a Microbenchmark class.The following code snippet shows how to add a benchmark to a JUnit test:
Kotlin
@RunWith(AndroidJUnit4::class) class SampleBenchmark { @get:Rule val benchmarkRule = BenchmarkRule() @Test fun benchmarkSomeWork() { benchmarkRule.measureRepeated { doSomeWork() } } }
Java
@RunWith(AndroidJUnit4.class) class SampleBenchmark { @Rule public BenchmarkRule benchmarkRule = new BenchmarkRule(); @Test public void benchmarkSomeWork() { final BenchmarkState state = benchmarkRule.getState(); while (state.keepRunning()) { doSomeWork(); } } }
To see how to write a benchmark, skip to Create a Microbenchmark class section.
Full project setup
To set up regular benchmarking rather than one-off benchmarking, isolate
benchmarks into their own module. This ensures that their configuration, such as
setting debuggable
to false
, is separate from regular tests.
Because Microbenchmark runs your code directly, you need to place the code you want to benchmark into a separate Gradle module and set dependency on that module as shown in the following figure.
To add a new Gradle module, you can use the module wizard in Android Studio. The
wizard creates a module that is pre-configured for benchmarking, with a
benchmark directory added and debuggable
set to false
.
Bumblebee (or newer)
- Right-click your project or module in the Project panel in Android Studio and click New > Module.
- Select Benchmark in the Templates pane.
- Select Microbenchmark as Benchmark module type.
- Type microbenchmark for the module name.
- Click Finish.
Arctic Fox
- Right-click your project or module in the Project panel in Android Studio and click New > Module.
- Select Benchmark in the Templates pane.
- Type microbenchmark for the module name.
- Click Finish.
After the module is created, change its build.gradle
file and add testImplementation
to the module containing code to benchmark:
Groovy
dependencies { // Note, that the module name may be different androidTestImplementation project(':benchmarkable') }
Kotlin
dependencies { // Note, that the module name may be different androidTestImplementation(project(":benchmarkable")) }
Create a Microbenchmark class
Benchmarks are standard instrumentation tests. To create a benchmark, use the
BenchmarkRule
class provided by the library. To benchmark activities, use
ActivityTestRule
or ActivityScenarioRule
. To benchmark UI code,
use @UiThreadTest
.
The following code shows a sample benchmark:
Kotlin
@RunWith(AndroidJUnit4::class) class SampleBenchmark { @get:Rule val benchmarkRule = BenchmarkRule() @Test fun benchmarkSomeWork() { benchmarkRule.measureRepeated { doSomeWork() } } }
Java
@RunWith(AndroidJUnit4.class) class SampleBenchmark { @Rule public BenchmarkRule benchmarkRule = new BenchmarkRule(); @Test public void benchmarkSomeWork() { final BenchmarkState state = benchmarkRule.getState(); while (state.keepRunning()) { doSomeWork(); } } }
Disable timing for setup
You can disable timing for sections of code you don't want to measure with the
runWithTimingDisabled{}
block. These sections usually represent some code
which you need to run on each iteration of the benchmark.
Kotlin
// using random with the same seed, so that it generates the same data every run private val random = Random(0) // create the array once and just copy it in benchmarks private val unsorted = IntArray(10_000) { random.nextInt() } @Test fun benchmark_quickSort() { // ... benchmarkRule.measureRepeated { // copy the array with timing disabled to measure only the algorithm itself listToSort = runWithTimingDisabled { unsorted.copyOf() } // sort the array in place and measure how long it takes SortingAlgorithms.quickSort(listToSort) } // assert only once not to add overhead to the benchmarks assertTrue(listToSort.isSorted) }
Java
private final int[] unsorted = new int[10000]; public SampleBenchmark() { // using random with the same seed, so that it generates the same data every run Random random = new Random(0); // create the array once and just copy it in benchmarks Arrays.setAll(unsorted, (index) -> random.nextInt()); } @Test public void benchmark_quickSort() { final BenchmarkState state = benchmarkRule.getState(); int[] listToSort = new int[0]; while (state.keepRunning()) { // copy the array with timing disabled to measure only the algorithm itself state.pauseTiming(); listToSort = Arrays.copyOf(unsorted, 10000); state.resumeTiming(); // sort the array in place and measure how long it takes SortingAlgorithms.quickSort(listToSort); } // assert only once not to add overhead to the benchmarks assertTrue(SortingAlgorithmsKt.isSorted(listToSort)); }
Try to minimize the amount of work done inside the measureRepeated
block, as
well as inside runWithTimingDisabled
. The measureRepeated
block is run
multiple times and it can affect the overall time needed to run the benchmark.
If you need to verify some results of a benchmark, you can assert the last
result instead of doing it every iteration of the benchmark.
Run the benchmark
In Android Studio, run your benchmark as you would any @Test
using the gutter
action next to your test class or method, as shown in the following image.
Alternatively, from the command line, run the connectedCheck
to run all of the
tests from specified Gradle module:
./gradlew benchmark:connectedCheck
Or a single test:
./gradlew benchmark:connectedCheck -P android.testInstrumentationRunnerArguments.class=com.example.benchmark.SampleBenchmark#benchmarkSomeWork
Benchmark results
After a successful Microbenchmark run, metrics are displayed directly in Android Studio and a full benchmark report with additional metrics and device information is available in JSON format.
JSON reports and any profiling traces are also automatically copied from device to host. These are written on the host machine at:
project_root/module/build/outputs/connected_android_test_additional_output/debugAndroidTest/connected/device_id/
By default, the JSON report is written to disk on-device in the test APK's
external shared media folder, which is typically located at
/storage/emulated/0/Android/media/**app_id**/**app_id**-benchmarkData.json
.
Configuration errors
The library detects the following conditions to ensure your project and environment are set up for release-accurate performance:
- Debuggable is set to
false
. - A physical device is being used (emulators are not supported).
- Clocks are locked if the device is rooted.
- Sufficient battery level on device (at least 25%).
If any of the checks previous fail, the benchmark reports an error to discourage inaccurate measurements.
To suppress specific error types as warnings and prevent them from halting the
benchmark, pass the error type in a comma-separated list to the instrumentation
argument androidx.benchmark.suppressErrors
.
This can be set either from your Gradle script as shown below:
Groovy
android { defaultConfig { … testInstrumentationRunnerArguments["androidx.benchmark.suppressErrors"] = "DEBUGGABLE,LOW-BATTERY" } }
Kotlin
android { defaultConfig { … testInstrumentationRunnerArguments["androidx.benchmark.suppressErrors"] = "DEBUGGABLE,LOW-BATTERY" } }
Suppressing errors lets the benchmark run in an incorrectly configured state,
and the output of the benchmark is intentionally renamed by prepending test
names with the error. For example, running a debuggable benchmark with the
suppression in the preceding snippet prepends test names with DEBUGGABLE_
.