User Manual

Rev 2.2-1.0.1

Mellanox Technologies

4.7.2.4 Querying the Hardware Time

Querying the hardware for time is done via the

ibv_exp_query_values verb.

For example:

ret = ibv_exp_query_values(context, IBV_EXP_VALUES_HW_CLOCK, &queried_values);

if (!ret && queried_values.comp_mask & IBV_EXP_VALUES_HW_CLOCK)

queried_time = queried_values.hwclock;

To change the queried time in nanoseconds resolution, use the IBV_

EXP_

VALUES_HW_CLOCK_NS

flag along with the hwclock_ns field.

ret = ibv_exp_query_values(context, IBV_EXP_VALUES_HW_CLOCK_NS, &queried_values);

if (!ret && queried_values.comp_mask & IBV_EXP_VALUES_HW_CLOCK_NS)

queried_time_ns = queried_values.hwclock_ns;

Querying the Hardware Time is available only on physical functions / native machines.

4.8 Ethernet VXLAN

4.8.1 Prerequisites

• HCA: ConnectX-3 Pro

• Firmware 2.31.5020 or higher

• RHEL7, Ubuntu 14.04 or upstream kernel 3.12.10 (or higher)

• DMFS enabled

4.8.2 Enabling VXLAN

To enable the vxlan offloads support load the mlx4_core driver with Device-Managed Flow-

steering (DMFS) enabled. Best would be to create an

/etc/modprobe.d/mlx4.conf file with the

following contents:

# enable DMFS --> enable VXLAN offloads on CX3-pro

options mlx4_core log_num_mgm_entry_size=-1

To verify VXLAN is enabled, verify the Ethernet net-device created by the mlx4_en driver

advertises the

NETIF_F_GSO_UDP_TUNNEL feature, which can be seen by the "eththool -K $DEV

| grep udp"

For example:

$ ethtool -k eth0 | grep udp_tnl

tx-udp_tnl-segmentation: on

Make sure that the VXLAN tunnel is set over UDP port 4789, which is the ConnectX firmware

default. If using standard Linux bridge (and not open vswitch) set the following

/etc/mod-

probe.d/vxlan.conf

options vxlan udp_port=4789