latency

Reference Documentation

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IntelĀ® PAC
Napatech SmartNIC
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Reference Information
Napatech Software Suite: latency
latency

latency

The latency tool is used to inspect packets sent via pktgen with time stamp injection applied. The tool calculates the round trip latency from when the packets are transmitted until they are received.Only ports running with the traffic generator profile can be used.

Note
The link speed -l, the timestamp method -t and the timestamp offset inject mode -i must match the values used by pktgen on the transmitting server. The values to use are displayed by pktgen. The -t and -i options must only be used if they are displayed by pktgen.

Syntax

latency -p -r -u -l [-i] [-t] [--help]

Commands
Command Description
--help, -h Displays the help
-p <port>The port to inspect
-r <secs>Reset interval - how often should statistics be reset
-u <secs>How often should the screen be updated
-l <speed>Link speed of the port used by pktgen is in Mbps.
Supported speeds: 10, 100, 1000, 10000, 40000
-t <timestamp method>Timestamp method of the port used by pktgen.
Supported values: SOF, EOF
-i <inject mode>Timestamp offset inject mode of the port used by pktgen.
Supported values: SOF, EOF

Output Example

  • Output from the command latency -p 0 -r 10 -u 1 -l1000
    --------------------+--------------------------------------------------+----------------+
                        |                  1 sec Sampling                  |      Last      |
                        |       Max      |      Min       |     Average    |   Round trip   |
    --------------------+----------------+----------------+----------------+----------------+
    Round trip in nsec  |              0 |              0 |              0 |              0 |
    --------------------+----------------+----------------+----------------+----------------+
    
    The round trip latency Max, Min, Average and Last are presented every second (-u 1) and reset every 10 seconds (-r 10).