From: William Horvath <william@horvath.blog> 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 --- dlls/ntdll/unix/sync.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) diff --git a/dlls/ntdll/unix/sync.c b/dlls/ntdll/unix/sync.c index e59f2113f5a..fd0878bf093 100644 --- a/dlls/ntdll/unix/sync.c +++ b/dlls/ntdll/unix/sync.c @@ -2485,22 +2485,7 @@ NTSTATUS WINAPI NtQuerySystemTime( LARGE_INTEGER *time ) { #ifdef HAVE_CLOCK_GETTIME struct timespec ts; - static clockid_t clock_id = CLOCK_MONOTONIC; /* placeholder */ - - if (clock_id == CLOCK_MONOTONIC) - { -#ifdef CLOCK_REALTIME_COARSE - struct timespec res; - - /* Use CLOCK_REALTIME_COARSE if it has 1 ms or better resolution */ - if (!clock_getres( CLOCK_REALTIME_COARSE, &res ) && res.tv_sec == 0 && res.tv_nsec <= 1000000) - clock_id = CLOCK_REALTIME_COARSE; - else -#endif /* CLOCK_REALTIME_COARSE */ - clock_id = CLOCK_REALTIME; - } - - if (!clock_gettime( clock_id, &ts )) + if (!clock_gettime( CLOCK_REALTIME, &ts )) { time->QuadPart = ticks_from_time_t( ts.tv_sec ) + (ts.tv_nsec + 50) / 100; } -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/10108