Synchronizing clocks of network interface cards of a server using system clock

A non-transitory computer readable storage medium storing instructions that when executed by one or more computer processors cause the one or more computer processors to perform steps comprising:

• determining, by a server, timestamps for packet transmission and reception, the server comprising a system clock and plurality of NICs, each NIC including a clock;
• synchronizing clocks of the plurality of NICS of the server with the system clock of the server, comprising, for each follower clock:
• determining a time offset and a frequency drift of the follower clock with respect to the system clock,
• determining correction signals for correcting the time offset and the frequency drift of the follower clock, and
• synchronizing the follower clock with the system clock by applying the correction signals to the follower clock;
• and
• responsive to synchronizing clocks of the plurality of NICS of the server with the system clock, determining timestamps for packet transmission and reception for the server based on the synchronized clocks of the plurality of NICs.

A computer system comprising:

• one or more computer processors;
• and
• a non-transitory computer readable storage medium storing instructions that when executed by one or more computer processors cause the one or more computer processors to perform steps comprising:
• determining, by a server, timestamps for packet transmission and reception, the server comprising a system clock and plurality of NICs, each NIC including a clock;
• synchronizing clocks of the plurality of NICS of the server with the system clock of the server, comprising, for each follower clock:
• determining a time offset and a frequency drift of the follower clock with respect to the system clock,
• determining correction signals for correcting the time offset and the frequency drift of the follower clock, and
• synchronizing the follower clock with the system clock by applying the correction signals to the follower clock;
• and
• responsive to synchronizing clocks of the plurality of NICS of the server with the system clock, determining timestamps for packet transmission and reception for the server based on the synchronized clocks of the plurality of NICs.