Hi,
There are following code in function ixgbe_xmit_pkts,
....
if ((txq->nb_tx_desc - txq->nb_tx_free) > txq->tx_free_thresh) {
ixgbe_xmit_cleanup(txq);
}
....
My understanding is, nb_tx_desc means total number of descriptors in
ring and nx_tx_free represents how many descriptors are available, so
txq->nb_tx_desc - txq->nb_tx_free means how many we have used. I'm not
quite understand the meaning of this comparison. Why is the condition
not something like "if (txq->nb_tx_free < tx_free_thresh)".
really appreciate if someone could help me on this.
Thanks
Qing
