Not able to determine time taken by Dart VM initialisation

[hrajwade96]

I am tracing app startup for Android device (Samsung Galaxy m51), In flutter devtools, I can see Warm-up frame at 4s 52ms 432us.
I am trying to analyse this delay and therefore need to find time taken by Dart VM initialisation as I am suspecting that could be one culprit.
In logs I can see a gap of 3.107s in MainActivity OnResume to main.dart first statement execution.
In Dev tools I can see gap of 4.52s before Warm-up frame and our own code execution.
I also added custom timeline traces in main.dart first line itself, its starting at ~4s
I am trying to verify if both are pointing to same delay.
As per my understanding Dart VM startup is somewhere between this time.

In another run I tried with '--trace-startup --profile'
in the startuptimeline.json i got :
{
"name": "DartVMInitializer",
"cat": "Embedder",
"tid": 4139,
"pid": 4139,
"ts": 14740213596,
"ph": "E",
"args": {}
},

this seems to be an end event but there is no subsequent start event in that file.

In dev tools I am not able to see much between FlutterEngineMainEnter and Warm-up frame.

Flutter doctor :
Flutter doctor results :

[✓] Flutter (Channel stable, 3.13.4, on macOS 14.0 23A344 darwin-arm64, locale en-IN)
• Flutter version 3.13.4 on channel stable at /Users/hrishikeshrajwade/Downloads/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 367f9ea16b (2 months ago), 2023-09-12 23:27:53 -0500
• Engine revision 9064459a8b
• Dart version 3.1.2
• DevTools version 2.25.0

[✓] Android toolchain - develop for Android devices (Android SDK version 32.1.0-rc1)
• Android SDK at /Users/hrishikeshrajwade/Library/Android/sdk
• Platform android-33, build-tools 32.1.0-rc1
• Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b829.9-10027231)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.0.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Build 15A507
• CocoaPods version 1.11.3

[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2022.3)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b829.9-10027231)

[✓] IntelliJ IDEA Ultimate Edition (version 2023.1)
• IntelliJ at /Applications/IntelliJ IDEA.app
• Flutter plugin version 73.0.4
• Dart plugin version 231.8109.91

[✓] VS Code (version 1.71.2)
• VS Code at /Users/hrishikeshrajwade/Downloads/Visual Studio Code.app/Contents
• Flutter extension version 3.60.0

[hrajwade96]

@kenzieschmoll any idea about this

[hrajwade96]

@kenzieschmoll any idea about this

[kenzieschmoll]

If you go to the CPU profiler tab and click the "Profile App Startup" button, that may help. CC @bkonyi and @dnfield for ideas about the "DartVMInitializer" timeline event.

[bkonyi]

There's a good chance that we're not seeing the start of the timeline event because it's started before the VM is initialized. Unless TRACE_EVENT0(...) can record to a systrace like recorder (I'm not sure of its implementation), the begin event will be dropped if it's supposed to be handled by the VM since the timeline recorder isn't initialized.