Very often people are looking at icache misses instead of something more precise when regarding perf effects due to code size/layout, etc. That more precise thing is frontend stalls: you only care about misses when they cause stalls; otherwise they are overlapped with actual work being done by the execution units.

You can measure frontend stalls on many recent intel chips by

IDQ_UOPS_NOT_DELIVERED.CORE

https://perfmon-events.intel.com/

Neoverse N1 from Arm has STALL_FRONTEND; see

https://developer.arm.com/documentation/PJDOC-466751330-5476...