CPU and Memory Monitoring
Capture CPU and memory usage of Android, iOS, Flutter, and React Native apps.
CPU and memory usage are captured every 5 seconds while the app is in the foreground. Readings appear on the session timeline.
CPU usage
A reading shows how much CPU the app is using. Sustained high usage drains the battery and heats up the device.
Android
Each reading is the average CPU usage since the previous one, across all cores: 100% means every core was fully busy. It's calculated from /proc/self/stat, where the OS records the clock ticks the process has spent on the CPU:
%CPU = 100 × ticks consumed / (clock tick rate × interval × number of cores)iOS
Each reading is the combined usage of all the app's non-idle threads, where 100% equals one fully busy core. On a device with multiple cores the value can go above 100%. The thread list comes from task_threads and each thread's usage from thread_info.
Memory usage
Android
Each reading reports:
- Max heap size: the most memory the runtime lets the app allocate on the Java heap. Allocating past it throws an
OutOfMemoryError. - Total heap size and free heap size: the heap memory the runtime has reserved so far, and how much of it is still free.
- RSS (resident set size): the physical memory held by the process, including native code and shared libraries. Shared pages are counted in full, so RSS overstates the app's own usage.
- Total PSS (proportional set size): physical memory with shared pages divided between the processes using them. PSS is the best value for judging the app's overall memory use.
- Native total heap size and native free heap size: total and free memory in the native heap.
The values come from:
| Value | Source |
|---|---|
| Heap sizes | Runtime.maxMemory, Runtime.totalMemory, Runtime.freeMemory |
| Total PSS | Debug.getMemoryInfo |
| Native heap sizes | Debug.getNativeHeapSize, Debug.getNativeHeapFreeSize |
| RSS | /proc/self/statm |
iOS
Each reading reports the app's physical memory footprint: the memory the app is responsible for, including memory the system has compressed. The system uses this value to decide which apps to terminate under memory pressure.
The footprint is read with task_info. When the value is unavailable, the SDK falls back to resident size, which excludes compressed memory and can underreport usage.
iOS Memory Deep Dive explains how Apple defines these values.
Flutter and React Native
Flutter and React Native apps don't collect these values themselves. The native Android or iOS SDK collects them using the APIs described above.
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