ETTrace 👽

Locally measure performance of your app, without Xcode or Instruments. Read all about it in the launch blog post

Building and Installing

You can add ETTrace as a Swift package, select the "ETTrace" library as the product to add, not "ETTraceRunner".

Alternatively, run ./build.sh to build the xcframework ETTrace.xcframework. Link the xcframework to your app.

Install the runner with brew install emergetools/homebrew-tap/ettrace

Using

Launch your app and run ettrace or ettrace --simulator. After profiling, the result will be displayed on https://emergetools.com/flamegraph

Note: Always launch the app by manually tapping the icon on the iOS homescreen, running the app through Xcode can result in inaccurate results.

dSYMs

You can point ettrace to a folder containing your dsyms with the --dsyms flag. If the dsyms are indexed by spotlight they will be automatically found and used.

Run at Launch

Use the flag --launch to start recording on app launch. When you first connect to the app using this flag, the app will force quit. On the next launch it will start profiling automatically and capture all of your main function. In some cases you need to record the first launch after an install. You can't use the --launch flag for this because that requires re-launching the app. Instead, add a boolean set to YES in your Info.plist with the key ETTraceRunAtStartup. You can then run ettrace regularly, without the --launch flag, and still start profiling at the start of app launch.

Under the hood

ETTrace spawns a new thread which captures a stacktrace of the main thread periodically. This is sampling based profiling. The sampling thread starts either when ettrace.framework is loaded (+load method), or when the CLI sends a message to the application. These control messages and the sampled data are communicated using PeerTalk.