Profile mode

Measure real performance with profile mode.

Profile mode

profile mode runs the Flutter app close to real device performance. There is no debug overhead, but DevTools still collects trace and build metrics. It is launched with flutter run --profile.

// Terminal
flutter run --profile

trace and build metrics

In profile mode, DevTools records build time, trace events and frame timings. You can see how long each frame takes to draw. Slow frames are marked yellow, very slow ones red.

Exercise List the profile command

In main, define a List<String> named cmd with the values 'flutter', 'run', '--profile' in order. Print the last element with print.

Show example solution

void main() {
  final cmd = ['flutter', 'run', '--profile'];
  print(cmd.last);
}

Test yourself

Which command launches profile mode?
- flutter test
- flutter run --profile
- flutter run
- flutter build
Show answer

flutter run --profile — Profile mode is launched with 'flutter run --profile'; plain 'flutter run' opens in debug mode.
Profile command
```
flutter run ____
```
Show answer
```
flutter run --profile
```
Profile mode matches

profile

Real performance mode
build

Widget creation process
trace

Event recording
frame

One drawing unit

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