Delivering high scroll performance

This post details a strategy for identifying and fixing scroll performance regressions in Meta's iOS News Feed. It introduces an on-device measurement technique using CADisplayLink to detect dropped frames and a signal-based profiling approach (SIGPROF) to capture main thread call stacks during high utilization periods. A dedicated, high-priority signaling thread is used to ensure timely signal firing. The captured backtraces are then symbolicated and aggregated for analysis.