-i
option. Enter the following command as root
:
~]# ptp4l -i em3 -m
Where em3 is the interface you wish to configure. Below is example output from ptp4l when the PTP
clock on the NIC is synchronized to a master:
~]# ptp4l -i em3 -m
selected em3 as PTP clock
port 1: INITIALIZING to LISTENING on INITIALIZE
port 0: INITIALIZING to LISTENING on INITIALIZE
port 1: new foreign master 00a069.fffe.0b552d-1
selected best master clock 00a069.fffe.0b552d
port 1: LISTENING to UNCALIBRATED on RS_SLAVE
master offset -23947 s0 freq +0 path delay 11350
master offset -28867 s0 freq +0 path delay 11236
master offset -32801 s0 freq +0 path delay 10841
master offset -37203 s1 freq +0 path delay 10583
master offset -7275 s2 freq -30575 path delay 10583
port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED
master offset -4552 s2 freq -30035 path delay 10385
The master offset value is the measured offset from the master in nanoseconds. The s0
, s1
, s2
strings indicate the different clock servo states: s0
is unlocked, s1
is clock step and s2
is locked. Once the servo is in the locked state (s2
), the clock will not be stepped (only slowly adjusted) unless the pi_offset_const
option is set to a positive value in the configuration file (described in the ptp4l(8)
man page). The adj
value is the frequency adjustment of the clock in parts per billion (ppb). The path delay value is the estimated delay of the synchronization messages sent from the master in nanoseconds. Port 0 is a Unix domain socket used for local PTP
management. Port 1 is the em3
interface (based on the example above.) INITIALIZING, LISTENING, UNCALIBRATED and SLAVE are some of possible port states which change on the INITIALIZE, RS_SLAVE, MASTER_CLOCK_SELECTED events. In the last state change message, the port state changed from UNCALIBRATED to SLAVE indicating successful synchronization with a PTP
master clock.
~]# systemctl start ptp4l
When running as a service, options are specified in the /etc/sysconfig/ptp4l
file. More information on the different ptp4l options and the configuration file settings can be found in the ptp4l(8)
man page.
/var/log/messages
. However, specifying the -m
option enables logging to standard output which can be useful for debugging purposes.
-S
option needs to be used as follows:
~]# ptp4l -i em3 -m -S
ptp4l
command as follows:
-P
-P
selects the peer-to-peer (P2P) delay measurement mechanism.
-E
-E
selects the end-to-end (E2E) delay measurement mechanism. This is the default.
-A
-A
enables automatic selection of the delay measurement mechanism.
Note
PTP
communication path must use the same mechanism to measure the delay. A warning will be printed when a peer delay request is received on a port using the E2E mechanism. A warning will be printed when a E2E delay request is received on a port using the P2P mechanism.