doc: improve hwtimestamp description

This commit is contained in:
Miroslav Lichvar 2016-12-14 13:30:17 +01:00
parent db312a5ff6
commit 5634e6b963

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@ -1780,10 +1780,11 @@ received from the specified network interface. The network interface controller
receptions, avoiding processing and queueing delays in the kernel, network
driver, and hardware. This can significantly improve the accuracy of the
timestamps and the measured offset, which is used for synchronisation of the
system clock. In order to get best results, it is necessary to enable HW
timestamping on both sides receiving and sending the packets (i.e. server and
client, or both peers), and also enable the interleaved mode with the *xleave*
option in the <<server,*server*>> or the <<peer,*peer*>> directive.
system clock. In order to get the best results, both sides receiving and
sending NTP packets (i.e. server and client, or two peers) need to use HW
timestamping. If the server or peer supports the interleaved mode, it needs to
be enabled by the *xleave* option in the <<server,*server*>> or the
<<peer,*peer*>> directive.
+
This directive is supported on Linux 3.19 and newer. The NIC must support HW
timestamping, which can be verified with the *ethtool -T* command. The list of