In addition to function of CLOCK_MONOTONIC, flag CLOCK_MONOTONIC_RAW can
also shield possiable impact of NTP, which can provide more robustness.
Suggested-by: Vitaly Kuznetsov<vkuznets@xxxxxxxxxx>
Signed-off-by: Yanan Wang<wangyanan55@xxxxxxxxxx>
Reviewed-by: Ben Gardon<bgardon@xxxxxxxxxx>
Reviewed-by: Andrew Jones<drjones@xxxxxxxxxx>