flowchart LR
    cpu["mach_absolute_time()<br/>x86_64 under Rosetta: nanoseconds"] --> cal["GetClockCalibration"]
    gpu["Metal counter heap<br/>24 MHz ticks everywhere"] --> cal
    cal -->|"before: units mixed"| bad["41.7× apart<br/>(1e9 / 24e6) ✘"]
    cal -->|"now: CPU value converted to ticks<br/>through the timebase"| good["same unit ✔"]