`RXMon`

Register an RX handler to dump received packets

RXMon

Shortest form: rxm.

Watch packets that reach the CPU through the SDK receive (RX) layer, by registering a shell callback that logs them. With no argument it prints Active bitmap for RX is <hex>., the DMA channels on which RX is running. Sub-commands must be written in full (case does not matter). An unknown word prints the help.

The logged packets appear only after debugmod diag rx has been enabled; rxmon start reminds you of that.

Only the bare command and rxmon show are read-only. The other forms act on the receive layer that SONiC’s syncd uses for host traffic.

Unvalidated

drivshell> rxmon

RXMon show

Print the state of the RX layer. Read-only.

Unvalidated

drivshell> rxmon show

RXMon init

Start the RX layer with the RXCfg settings, without registering the logging callback. It refuses with RX is already running if RX is already started, which is normally the case under SONiC. It also refuses while PacketWatcher runs.

Unvalidated

drivshell> rxmon init

RXMon start

Start RX if needed, and register the logging callback for all CPU queues. Packets that the callback handles may no longer reach SONiC’s own receive handler, so this can disturb host traffic.

Unvalidated

drivshell> debugmod diag rx
drivshell> rxmon start

RXMon stop

Stop the RX layer and remove the logging callback.

Warning

This stops packet reception for the whole unit, not only for rxmon. Under SONiC it breaks the host packet path. Do not use on a production switch.

Unvalidated

drivshell> rxmon stop

RXMon enqueue [<n>]

Make the callback hold packets and free them in batches of at least <n> (default 1) in a separate thread. rxmon -enqueue switches this off again.

Unvalidated

drivshell> rxmon enqueue 16

Built-in help

Parameters [init|start|stop|show|[-]enqueue [n]]
With no parameters, show whether or not active.
    init:           Initialize the RX API, but don't register handler
    start:          Call RX start with local pkt dump routine
                    Modify the configuration with the rxcfg command
    stop:           Call RX stop
    [-]enqueue [n]: Enqueue packets to be freed later in thread
                    If n > 0, enqueue at least n pkts before freeing
    stop:           Call RX stop
    show:           Call RX show