Diagnosing choppy scrolling performance
WHAT IT TESTS: profiling discipline over guessing. OUTLINE: reach for Instruments, especially the Time Profiler and Core Animation/Hangs tools, and look for main-thread work and dropped frames. RED FLAG: blindly optimizing without measuring first.
WHAT IT TESTS: whether you measure before optimizing and know Apple's tooling. ANSWER OUTLINE: open Instruments and run the Time Profiler to find expensive main-thread work during scroll, plus the Animation Hitches or Core Animation instrument to count dropped frames; you are looking for synchronous work on the main thread such as image decoding, layout, or autolayout thrash that pushes a frame past the 16.6ms budget at 60Hz. RED FLAG: guessing the cause and rewriting code without a measurement, or only checking CPU in isolation.
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- #ios
- #performance
- #instruments
- #scrolling
- #profiling
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