---
title: "Legacy Profiling"
description: "Learn about the legacy profilers and how to use them on devices running Android versions earlier than Android 15."
url: https://docs.sentry.io/platforms/android/profiling/legacy/
---

# Legacy Profiling | Sentry for Android

##### Legacy

This page documents Sentry's legacy Android profilers. On Android 15 (API level 35) and higher, the recommended [ProfilingManager (Perfetto) based UI Profiling](https://docs.sentry.io/platforms/android/profiling.md) (available since SDK version `8.47.0`) is used automatically. On devices below Android 15, the SDK automatically falls back to the legacy profiler documented here.

There are two legacy profiling implementations:

* **Legacy UI Profiling**, which samples threads using the Android runtime's `tracer`. It supports the same `manual` and `trace` lifecycle modes as the current UI Profiling, but uses the `tracer` backend instead of the ProfilingManager.
* **Transaction-based profiling**, the oldest implementation, which runs only alongside performance transactions and is limited to 30 seconds.

##### Important

Legacy UI Profiling and transaction-based profiling use the Android runtime's `tracer` under the hood to sample threads. There are known issues that this `tracer` can cause crashes in certain circumstances. See this [troubleshooting ](https://docs.sentry.io/platforms/android/profiling/troubleshooting.md#i-see-an-elevated-number-of-crashes-in-the-android-runtime-when-profiling-is-activated)entry for more information. The ProfilingManager (Perfetto) based [UI Profiling](https://docs.sentry.io/platforms/android/profiling.md) is not affected by these issues.

## [Legacy UI Profiling](https://docs.sentry.io/platforms/android/profiling/legacy.md#legacy-ui-profiling)

Legacy UI Profiling is available starting with SDK version `8.7.0` and is supported on API level 21 and up.

The SDK uses the legacy profiler automatically on devices below Android 15 (API level 35); on Android 15 and higher it uses the ProfilingManager (Perfetto) backend instead. Configure UI Profiling exactly as described in the [UI Profiling documentation](https://docs.sentry.io/platforms/android/profiling.md) — the same `profileSessionSampleRate` and `profileLifecycle` options apply. To disable the legacy profiler, and turn off profiling on older devices entirely, set [`enableLegacyProfiling`](https://docs.sentry.io/platforms/android/configuration/options.md#enableLegacyProfiling) to `false`.

UI Profiling supports two modes: `manual` and `trace`. These modes are mutually exclusive and cannot be used at the same time.

In `manual` mode, profiling data collection is managed via calls to `Sentry.startProfiler` and `Sentry.stopProfiler`. You are entirely in control of when the profiler runs.

In `trace` mode, the profiler manages its own start and stop calls, which are based on spans: the profiler runs while there is at least one active sampled span and stops when there are no active sampled spans.

Unlike the ProfilingManager backend, the legacy profiler supports profiling the app start process through the `startProfilerOnAppStart` option.

### [Enabling Trace Lifecycle Legacy UI Profiling](https://docs.sentry.io/platforms/android/profiling/legacy.md#enabling-trace-lifecycle-legacy-ui-profiling)

To enable trace profiling, set the lifecycle to `trace`. Trace profiling requires tracing to be enabled.

Check out the [tracing setup documentation](https://docs.sentry.io/platforms/android/tracing.md) for more detailed information on how to configure sampling. Setting the sample rate to 1.0 means all transactions will be captured.

By default, some transactions will be created automatically for common operations like loading a view controller/activity and app startup.

```xml
<application>
  <meta-data
    android:name="io.sentry.dsn"
    android:value="https://<key>@o<orgId>.ingest.sentry.io/<projectId>"
  />
  <!-- Enable tracing, needed for profiling `trace` mode, adjust in production env -->
  <meta-data
    android:name="io.sentry.traces.sample-rate"
    android:value="1.0"
  />
  <!-- Enable UI profiling, adjust in production env. This is evaluated only once per session -->
  <meta-data
    android:name="io.sentry.traces.profiling.session-sample-rate"
    android:value="1.0"
  />
  <meta-data
    android:name="io.sentry.traces.profiling.lifecycle"
    android:value="trace"
  />
  <!-- Enable profiling on app start. The app start profile will be stopped automatically when the app start root span finishes -->
  <meta-data
    android:name="io.sentry.traces.profiling.start-on-app-start"
    android:value="true"
  />
</application>
```

*Other available variations of the above snippet: java, kotlin*

### [Enabling Manual Lifecycle Legacy UI Profiling](https://docs.sentry.io/platforms/android/profiling/legacy.md#enabling-manual-lifecycle-legacy-ui-profiling)

To enable manual profiling, set the lifecycle to `manual`. Manual profiling does not require tracing to be enabled.

```xml
<application>
  <meta-data
    android:name="io.sentry.dsn"
    android:value="https://<key>@o<orgId>.ingest.sentry.io/<projectId>"
  />
  <!-- Enable UI profiling, adjust in production env. This is evaluated only once per session -->
  <meta-data
    android:name="io.sentry.traces.profiling.session-sample-rate"
    android:value="1.0"
  />
  <meta-data
    android:name="io.sentry.traces.profiling.lifecycle"
    android:value="manual"
  />
  <!-- Enable profiling on app start. The app start profile has to be stopped through Sentry.stopProfiler() -->
  <meta-data
    android:name="io.sentry.traces.profiling.start-on-app-start"
    android:value="true"
  />
</application>
```

*Other available variations of the above snippet: java, kotlin*

## [Transaction-Based Profiling](https://docs.sentry.io/platforms/android/profiling/legacy.md#transaction-based-profiling)

This is the oldest profiling implementation and will eventually be deprecated. We recommend upgrading to the [ProfilingManager (Perfetto) based UI Profiling](https://docs.sentry.io/platforms/android/profiling.md). The same behavior, without the 30 seconds limitation, can be achieved with the trace lifecycle. In order to upgrade, you also need to remove the [transaction-based profiling options](https://docs.sentry.io/platforms/android/configuration/options.md#transaction-based-profiling-options) from your configuration.

Android transaction-based profiling is available starting in SDK version `6.16.0` and is supported on API level 22 and up. App start profiling is available starting in SDK version `7.3.0`.

Transaction-based profiling only runs in tandem with performance transactions that were started either automatically or manually with `Sentry.startTransaction`, and stops automatically after 30 seconds (unless you manually stop it earlier). Naturally, this limitation makes it difficult to get full coverage of your app's execution.

```xml
<application>
  <meta-data
    android:name="io.sentry.dsn"
    android:value="https://<key>@o<orgId>.ingest.sentry.io/<projectId>"
  />
  <!-- Enable tracing, needed for legacy profiling, adjust in production env -->
  <meta-data
    android:name="io.sentry.traces.sample-rate"
    android:value="1.0"
  />
  <!-- Enable transaction-based profiling, adjust in production env. This is relative to traces sample rate -->
  <meta-data
    android:name="io.sentry.traces.profiling.sample-rate"
    android:value="1.0"
  />
  <!-- Enable profiling on app start -->
  <meta-data
    android:name="io.sentry.traces.profiling.enable-app-start"
    android:value="true"
  />
</application>
```

*Other available variations of the above snippet: java, kotlin*

The SDK won't run app start profiling the very first time the app runs, as the SDK won't have read the options by the time the profile should run. The SDK will set the `isForNextAppStart` flag in `TransactionContext` if app start profiling is enabled.