heapprofd allows you to attribute memory usage to functions for Android services and apps.
For documentation, see https://perfetto.dev/docs/data-sources/native-heap-profiler.
For design doc, see https://perfetto.dev/docs/design-docs/heapprofd-design.
android: connects to the system heapprofd. The client API will need to have been built at exactly the same version. This means this can only be used by the API shipped in the platform.
standalone: executes an in-process heapprofd. Can be used on old platform versions.
noop: ignores all calls to the client API. This can be used as a stand-in when compiling, or when executing without profiling.
bionic: uses bionic malloc dispatch to intercept allocation functions on Android. This works by placing a library on a pre-defined path, which gets loaded by Bionic.
glibc: generates a library exposing the allocation functions. This library should be used for LD_PRELOAD and uses the glibc specific symbols like __libc_malloc to use the system allocator.
| GN target | factory | interceptor | distribution |
|---|---|---|---|
| heapprofd_client | android | bionic | platform |
| heapprofd_client_api | android | none | platform |
| heapprofd_glibc_preload | standalone | glibc | unbundled |
| heapprofd_standalone_client | standalone | none | unbundled |
| heapprofd_api_noop | noop | none | unbundled |
For development, you might want to get a heap profile of heapprofd while it is profiling something else. For that reason, we allow two heapprofds to run on the system. The secondary heapprofd can then profile your primary one.
To do this, first make sure that heapprofd is running by setting the property
adb shell su root setprop persist.heapprofd.enable 1
Take note of its PID.
adb shell ps -e | grep heapprofd
Then, move away the primary heapprofd socket to make space for the secondary one
adb shell su root mv /dev/socket/heapprofd /dev/socket/heapprofd_primary
Start the secondary heapprofd
adb shell su root start heapprofd_secondary
Now we can start the profile of the primary heapprofd (using the secondary). Leave this session running.
tools/heap_profile -p ${PID_FROM_ABOVE}
Now move back the original socket
adb shell su root unlink /dev/socket/heapprofd adb shell su root mv /dev/socket/heapprofd_primary /dev/socket/heapprofd
Now all subsequent profiles will be done on the primary heapprofd again, with the secondary observing it.