[$] Providing precise time over the network

Handling time in a networked environment is never easy. TheNetwork Time Protocol (NTP) has been used to synchronize clocks across theinternet for almost 40 years - but, as computers and networks get faster, thedegree of synchronization it offers is not sufficient for some use cases. ThePrecision Time Protocol (PTP) attempts to provide more precisetime synchronization, at theexpense of requiring dedicated kernel and hardwaresupport. The Linux kernel hassupported PTP since 2011, but the protocol has recently seenincreasing use in data centers. As PTP becomes more widespread, it may beuseful to have an idea how it compares to NTP.