Hi Beilei,
I want to make sure my understanding of the TX path is correct.
Following is my understanding.
1) The RS bit must be set in the TX descriptors to ask the NIC to report back
the send status.
2) The NIC reports the send completion by setting the DTYPE field to 0xf. This
also indicates that all the earlier descriptors are also done sending the
packets.
3) The check "if (txq->nb_tx_free < txq->tx_free_thresh)" is mainly to ensure
that we do not check the "descriptor done" status too often.
Is my understanding correct?
Thank you,
Honnappa
