User Manual

Driver FeaturesRev 2.2-1.0.1

Mellanox Technologies

4.6.8.3 Additional Tools

tc tool compiled with the

sch_mqprio module is required to support kernel v2.6.32 or higher.

This is a part of

iproute2 package v2.6.32-19 or higher. Otherwise, an alternative custom sysfs

interface is available.

•

mlnx_qos tool (package: ofed-scripts) requires python >= 2.5

•

tc_wrap.py (package: ofed-scripts) requires python >= 2.5

4.7 Ethernet Time-Stamping

4.7.1 Ethernet Time-Stamping Service

Time Stamping is currently supported in ConnectX®-3/ConnectX®-3 Pro adapter

cards only.

Time stamping is the process of keeping track of the creation of a packet. A time-stamping ser-

vice supports assertions of proof that a datum existed before a particular time. Incoming packets

are time-stamped before they are distributed on the PCI depending on the congestion in the PCI

buf

fers. Outgoing packets are time-stamped very close to placing them on the wire.

4.7.1.1 Enabling Time Stamping

Time-stamping is off by default and should be enabled before use.

 To enable time stamping for a socket:

• Call setsockopt() with SO_TIMESTAMPING and with the following flags:

SOF_TIMESTAMPING_TX_HARDWARE: try to obtain send time stamp in hardware

SOF_TIMESTAMPING_TX_SOFTWARE: if SOF_TIMESTAMPING_TX_HARDWARE is off or

fails, then do it in software

SOF_TIMESTAMPING_RX_HARDWARE: return the original, unmodified time stamp

as generated by the hardware

SOF_TIMESTAMPING_RX_SOFTWARE: if SOF_TIMESTAMPING_RX_HARDWARE is off or

fails, then do it in software

SOF_TIMESTAMPING_RAW_HARDWARE: return original raw hardware time stamp

SOF_TIMESTAMPING_SYS_HARDWARE: return hardware time stamp transformed to

the system time base

SOF_TIMESTAMPING_SOFTWARE: return system time stamp generated in

software

SOF_TIMESTAMPING_TX/RX determine how time stamps are generated.

SOF_TIMESTAMPING_RAW/SYS determine how they are reported

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