[$] 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.