I have two questions:
*** First question:
In this page of Android developers website: https://developer.android.com/studio/run/emulator-commandline.html
It is said that there's a -trace option for the emulator. However, when I run the following command:
me@my_computer:~$ $SDK_ROOT/tools/emulator -avd Nexus_4_API_19_ARM -trace $OUTPUT_FILE
I get this error:
unknown option: -trace
please use -help for a list of valid options
Also, when I run this command:
me@my_computer:~$ $SDK_ROOT/tools/emulator -help | grep trace
the result is empty.
Is this really an inconsistency between the website manual and the command line help of the emulator?
*** Second question:
Looking for a way of tracing, I found that the -qemu option has something like this:
me@my_computer:~$ $SDK_ROOT/tools/emulator -qemu -h | grep trace
-trace [events=<file>][,file=<file>]
But when I add the -qemu option:
me@my_computer:~$ $SDK_ROOT/tools/emulator -avd Nexus_4_API_19_ARM -qemu -trace file=$OUTPUT_FILE
what I get is:
$SDK_ROOT/tools/emulator64-arm: invalid option -- '-trace'
At the QEMU documention web page (http://wiki.qemu.org/download/qemu-doc.html#index-_002dtrace), it is said that:
-trace [events=file][,file=file]
...
file=file
Log output traces to file. This option is only available if QEMU has been compiled with the simple tracing backend.
Is this the reason that -qemu -trace doesn't work in Android emulator?
I'd appreciate it if someone helps me on this issue.
Any other suggestions for collecting traces (especially instruction traces) of a real or virtual Android device are appreciated as well.
Thanks
Sadly, the manual page is outdated. As of now, emulator doesn't support own tracing features and it build the QEMU engine with no tracing support as well. I'll file a bug to update the manual.