This is required for deterministic timekeeping, as the CLOCK_REALTIME_COARSE path depends on the scheduling tickrate (CONFIG_HZ) the kernel was built with. Increasing the kernel tickrate to 1000 or greater will then result in decreased accuracy for anything calling NtQuerySystemTime, which some anti-cheat/DRM schemes are unhappy about (see wine bug). Being in the vDSO, clock_gettime(CLOCK_REALTIME) should not meaningfully impact performance when compared to CLOCK_REALTIME_COARSE. Furthermore, the CLOCK_REALTIME_COARSE code path is completely untested in CI, because the current CI runners are configured with CONFIG_HZ < 1000. Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59420 -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10108