[$] Providing precise time over the network

Handling time in a networked environment is never easy. The

Network Time Protocol (NTP) has been used to synchronize clocks across the
internet for almost 40 years — but, as computers and networks get faster, the
degree of synchronization it offers is not sufficient for some use cases. The

Precision Time Protocol (PTP) attempts to provide more precise
time synchronization, at the
expense of requiring dedicated kernel and hardware
support. The Linux kernel has

supported PTP since 2011, but the protocol has recently seen

increasing use in data centers. As PTP becomes more widespread, it may be
useful to have an idea how it compares to NTP.