Xamarin.Android Troubleshooting Snippets

snippets.md

Diagnosing JIT / AOT Timings

1. After installing the .apk, open up an Android Device Monitor to the Logcat tab, or use adb logcat
2. Look for a log under ActivityManager that has the message Displayed Activity: <timing>

EX:

07-28 12:48:38.356: I/ActivityManager(769): Displayed com.myapplication.App1/md58adf3f2592a7497b73592b5e766304c2.MainActivity: +1s990ms

3. Enable android:debugging="true" in you application or set your Configuration to Debug

4. Set the debug.mono.log to timing to generate counters.txt and methods.txt files

https://developer.xamarin.com/guides/android/advanced_topics/environment/

https://developer.xamarin.com/guides/android/advanced_topics/environment/#debug.mono.log

https://developer.xamarin.com/guides/android/advanced_topics/environment/#Example

You can also use adb shell setprop debug.mono.log timing.

# Enable timing messages to be created
debug.mono.log=timing

5. Take the counters.txt and methods.txt off the device

adb shell run-as com.myapplication.App1 cat files/.__override__/counters.txt > counters-FullAOT.txt
adb shell run-as com.myapplication.App1 cat files/.__override__/methods.txt > methods-FullAOT.txt

• counters.txt - JIT diagnostics everytime Runtime.register() is invoked. Note: Typically you care about how much time is spent JITing. i.e. the Total time spent JITting (sec) value.
• methods.txt - List of every method that is JIT'd in the order it is JIT'd. Note: Typically you care about how many lines methods.txt has in total. i.e. 1562 lines

Ensuring AOT is working

In adb logcat look for the following tag:

AOT: image '<ASSEMBLY NAME>.dll.so' found.

Otherwise you'll see an error similar to:

AOT: image '<ASSEMBLY NAME>.so' not found: dlopen failed: cannot locate symbol "__aeabi_memset" referenced by "/data/app/com.myapplication.App1-1/lib/arm/libaot-<ASSEMBLY NAME>.dll.so"...