Is PTP supported over macvlan interfaces?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux (RHEL) 7, 8
  • kernel version 3.10.0-693.5.2.el7.x86_64
  • linuxptp-1.8-3.el7_4.1.x86_64

Issue

ptp4l service doesn't work on macvlan interfaces.

Resolution

The macvlan driver doesn't have ptp support, so you should configure PTP in a NIC with a supported driver.

Current plan is to introduce PTP support on macvlan interfaces in future RHEL 8 minor release.

Root Cause

The macvlan driver didn't have PTP support previously.

Diagnostic Steps

Command fails when launching ptp4l on macvlan interface:

ptp4l[3233.524]: interface 'macvlan' does not support requested timestamping mode
failed to create a clock

Even if the 'physical' interface supports TIMESTAMPING, the macvlan does not:

$ ethtool -T ens32 
Time stamping parameters for ens32:
Capabilities:
        software-transmit     (SOF_TIMESTAMPING_TX_SOFTWARE)
        software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
        software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
PTP Hardware Clock: none
Hardware Transmit Timestamp Modes: none
Hardware Receive Filter Modes: none

$ ethtool -T macvlan_ens32 
Cannot get device time stamping settings: No such device
Time stamping parameters for macvlan@ens32:

$ ip address
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:xx:xx:xx brd ff:ff:ff:ff:ff:ff
3: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:xx:xx:xx brd ff:ff:ff:ff:ff:ff
4: macvlan@ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether c6:87:a9:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    inet 10.x.x.x/24 brd 10.x.x.255 scope global macvlan
       valid_lft forever preferred_lft forever

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