Oh and just to add, we run ptp4l on the host in unicast mode since we
have no more than 5 or 6 hosts that need to be synced all tied via their
control NIC to the same VLAN.
--
cheers,
Hussam
(Hussamuddin Nasir)
Netlab & GENI Operations Team
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Laboratory for Adv. Networking Phone : (859)218-0059
James F Hardymon Building Fax : (859)323-3740
301 Rose Street, Rm 237 E-mail : na...@netlab.uky.edu
Lexington, KY 40506-0495 Web : http://www.netlab.uky.edu
University of Kentucky
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On 11/12/20 9:49 PM, Hussamuddin Nasir wrote:
Hi Paul and Richard,
We are in a similar boat where we have multiple Mellanox Connect
X5/6 cards on a Dell server that will allocated to VMs as PCI
passthru. The control NIC on the host which is also a Mellanox CX5
receives PTP signals from a PTP master clock. The PCI pass thru cards
have no incoming PTP signals from the network. So Here's our approach
1. Use ptp4l to sync the Host's control NIC using PTP
2. Use phc2sys in automode on the host to sync the systemclock
3. The VMs launched on this hosts are KVMs. Linux kernel has a device
module called ptp_kvm that emulates a PTP clock device inside the
VM.4. So depending on the number of Connect X5/6 NICs sent via PCI
passthu to this NIC, we launch multiple phc2sys daemons inside the VM.
Each daemon would take the /dev/ptp_kvm device as source signal and
the /dev/ptpN (or the NIC name) as the sink.
For this to work in the ubuntu VMS we just made copies of the systemd
startup script for phc2sys (one for each NIC and appropriately renamed
the script). Then in each script edited it to remove its dependency on
ptp4l since that is not needed inside the VM
The logs suggested that the delay path was off by +/- 4ns which was
acceptable for us.
Richard: Does this sound like a workable solution.. ?
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