User Manual

Rev 2.2-1.0.1

Mellanox Technologies

a pending bounced packet is ready for reading as far as select() is concerned. If the outgoing

packet has to be fragmented, then only the first fragment is time stamped and returned to the

sending socket.

When time-stamping is enabled, VLAN stripping is disabled. For more info please

refer to Documentation/networking/timestamping.txt in kernel.org

4.7.1.3 Querying Time Stamping Capabilities via ethtool

 To display Time Stamping capabilities via ethtool:

• Show Time Stamping capabilities

ethtool -T eth<x>

Example:

ethtool -T eth0

Time stamping parameters for p2p1:

Capabilities:

hardware-transmit (SOF_TIMESTAMPING_TX_HARDWARE)

software-transmit (SOF_TIMESTAMPING_TX_SOFTWARE)

hardware-receive (SOF_TIMESTAMPING_RX_HARDWARE)

software-receive (SOF_TIMESTAMPING_RX_SOFTWARE)

software-system-clock (SOF_TIMESTAMPING_SOFTWARE)

hardware-raw-clock (SOF_TIMESTAMPING_RAW_HARDWARE)

PTP Hardware Clock: 1

Hardware Transmit Timestamp Modes:

off (HWTSTAMP_TX_OFF)

on (HWTSTAMP_TX_ON)

Hardware Receive Filter Modes:

none (HWTSTAMP_FILTER_NONE)

all (HWTSTAMP_FILTER_ALL)

For more details on PTP Hardware Clock, please refer to:

https://www.kernel.org/doc/Documentation/ptp/ptp.txt

4.7.2 RoCE Time Stamping

RoCE Time Stamping is currently at beta level.

Please be aware that everything listed here is subject to change.

RoCE Time Stamping allows you to stamp packets when they are sent to the wire / received from

the wire. The time stamp is given in a raw hardware cycles, but could be easily converted into

hardware referenced nanoseconds based time. Additionally, it enables you to query the hardware

for the hardware time, thus stamp other application's event and compare time.

4.7.2.1 Query Capabilities

Time stamping is available if and only the hardware reports it is capable of reporting it. To verify

whether RoCE

Time Stamping is available, run

ibv_exp_query_device.