> Instrumentation rarely modifies the execution profile to the point that the numbers are 'worthless' or 'random'. My rule of thumb is that self times near the leaves of the callgraph are more accurate than self times further up the graph but having some indication of timing is important.
I was only talking about the instrumentation system on Android, not the one anywhere else. It forced ART to fall back to interpreted mode, so no JIT at all, which massively balloons the cost of certain things like single-line getters or JNI calls. It was actually useless as a performance tool of any kind, which is why the recommendation for years has been to ignore the numbers it produced. It's great at answering questions about what a given function ends up doing, but that's it.
I was only talking about the instrumentation system on Android, not the one anywhere else. It forced ART to fall back to interpreted mode, so no JIT at all, which massively balloons the cost of certain things like single-line getters or JNI calls. It was actually useless as a performance tool of any kind, which is why the recommendation for years has been to ignore the numbers it produced. It's great at answering questions about what a given function ends up doing, but that's it.
If you want low-overhead timelines with duration numbers that actually have meaning that's the job of systrace ( https://developer.android.com/studio/command-line/systrace.h... ).