derek.holloway
7502bf64a4
3.9 KiB
Quickstart: Callstack sampling on Android
Prerequisites
- ADB installed.
- A device running Android T+.
- Either a debuggable (
userdebug/eng) Android image, or the apps to be profiled need to be marked as profileable or debuggable in their manifests.
Capture a CPU profile
Linux or macOS
Make sure adb is installed and in your PATH.
adb devices -l
If more than one device or emulator is reported you must select one upfront as follows:
export ANDROID_SERIAL=SER123456
Download cpu_profile (if you don't have a Perfetto checkout):
curl -LO https://raw.githubusercontent.com/google/perfetto/main/tools/cpu_profile
chmod +x cpu_profile
Then, start profiling. For example, to profile the processes com.android.foo
and com.android.bar, use:
./cpu_profile -n "com.android.foo,com.android.bar"
By default, profiling runs until manually terminated manually. To set a specific duration for recording (e.g. 30 seconds), use:
./cpu_profile -n "com.android.foo,com.android.bar" -d 30000
To change how frequently stack samples are recorded (e.g. 120 samples per
second), set the -f argument:
./cpu_profile -n "com.android.foo,com.android.bar" -f 120
You can also pass in parts of the names of the processes you want to profile by
enabling --partial-matching/-p. This matches processes that are already
running when profiling is started. For instance, to profile the processes
com.android.foo and com.android.bar, run:
./cpu_profile -n "foo,bar" -p
You can also pass in a custom Perfetto config, which
overrides all of the options above, using the -c argument:
./cpu_profile -c "path/to/perfetto.config"
To change where profiles are output, use the -o argument:
./cpu_profile -n "com.android.foo,com.android.bar" -o "path/to/output/directory"
Windows
Make sure that the downloaded adb.exe is in the PATH.
set PATH=%PATH%;%USERPROFILE%\Downloads\platform-tools
adb devices -l
If more than one device or emulator is reported you must select one upfront as follows:
set ANDROID_SERIAL=SER123456
Download the
cpu_profile
script. Then, start profiling. For example, to profile the processes
com.android.foo and com.android.bar, use:
python3 /path/to/cpu_profile -n "com.android.foo,com.android.bar"
Please see the Linux or maxOS section for more examples.
Symbolization
You may need to symbolize the collected profiles if they are missing symbols. See this for more details on how to do this.
For example, to profile and symbolize the profiles for the process
com.android.foo, run:
PERFETTO_SYMBOLIZER_MODE=index PERFETTO_BINARY_PATH=path/to/directory/with/symbols/ ./cpu_profile -n "com.android.foo"
View profile
Upload the raw-trace or symbolized-trace file from the output directory to
the Perfetto UI and click and drag over one or more
of the diamond markers in the UI track named "Perf Samples" for the processes
that you selected for profiling. Each diamond marker represents a snapshot of
the call-stack at that point on the timeline.
cpu_profile will also write separate profiles for each process that it
profiled in the output directory, and those can be visualized using
pprof. You can merge them into one
by passing all of them to pprof, e.g.
pprof /tmp/perf_profile-240105114948clvad/*.