Hi,
> Add support to the ixgbe driver for the API rte_eth_tx_done_cleanup
> to force free consumed buffers on Tx ring.
>
> Signed-off-by: Chenxu Di <chenxux...@intel.com>
> ---
> drivers/net/ixgbe/ixgbe_ethdev.c | 2 +
> drivers/net/ixgbe/ixgbe_rxtx.c | 116 +++++++++++++++++++++++++++++++
> drivers/net/ixgbe/ixgbe_rxtx.h | 2 +
> 3 files changed, 120 insertions(+)
>
> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> b/drivers/net/ixgbe/ixgbe_ethdev.c
> index 2c6fd0f13..0091405db 100644
> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> @@ -601,6 +601,7 @@ static const struct eth_dev_ops ixgbe_eth_dev_ops = {
> .udp_tunnel_port_add = ixgbe_dev_udp_tunnel_port_add,
> .udp_tunnel_port_del = ixgbe_dev_udp_tunnel_port_del,
> .tm_ops_get = ixgbe_tm_ops_get,
> + .tx_done_cleanup = ixgbe_tx_done_cleanup,
Don't see how we can have one tx_done_cleanup() for different tx functions?
Vector and scalar TX path use different format for sw_ring[] entries.
Also offload and simile TX paths use different method to track used/free
descriptors,
and use different functions to free them:
offload uses tx_entry next_id, last_id plus txq. last_desc_cleaned, while
simple TX paths use tx_next_dd.
> };
>
> /*
> @@ -649,6 +650,7 @@ static const struct eth_dev_ops ixgbevf_eth_dev_ops = {
> .reta_query = ixgbe_dev_rss_reta_query,
> .rss_hash_update = ixgbe_dev_rss_hash_update,
> .rss_hash_conf_get = ixgbe_dev_rss_hash_conf_get,
> + .tx_done_cleanup = ixgbe_tx_done_cleanup,
> };
>
> /* store statistics names and its offset in stats structure */
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index fa572d184..520b9c756 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
> @@ -2306,6 +2306,122 @@ ixgbe_tx_queue_release_mbufs(struct ixgbe_tx_queue
> *txq)
> }
> }
>
> +int ixgbe_tx_done_cleanup(void *q, uint32_t free_cnt)
That seems to work only for offload(full) TX path (ixgbe_xmit_pkts).
Simple(fast) path seems not covered by this function.
> +{
> + struct ixgbe_tx_queue *txq = (struct ixgbe_tx_queue *)q;
> + struct ixgbe_tx_entry *sw_ring;
> + volatile union ixgbe_adv_tx_desc *txr;
> + uint16_t tx_first; /* First segment analyzed. */
> + uint16_t tx_id; /* Current segment being processed. */
> + uint16_t tx_last; /* Last segment in the current packet. */
> + uint16_t tx_next; /* First segment of the next packet. */
> + int count;
> +
> + if (txq == NULL)
> + return -ENODEV;
> +
> + count = 0;
> + sw_ring = txq->sw_ring;
> + txr = txq->tx_ring;
> +
> + /*
> + * tx_tail is the last sent packet on the sw_ring. Goto the end
> + * of that packet (the last segment in the packet chain) and
> + * then the next segment will be the start of the oldest segment
> + * in the sw_ring.
Not sure I understand the sentence above.
tx_tail is the value of TDT HW register (most recently armed by SW TD).
last_id is the index of last descriptor for multi-seg packet.
next_id is just the index of next descriptor in HW TD ring.
How do you conclude that it will be the ' oldest segment in the sw_ring'?
Another question why do you need to write your own functions?
Why can't you reuse existing ixgbe_xmit_cleanup() for full(offload) path
and ixgbe_tx_free_bufs() for simple path?
Yes, ixgbe_xmit_cleanup() doesn't free mbufs, but at least it could be used
to determine finished TX descriptors.
Based on that you can you can free appropriate sw_ring[] entries.
>This is the first packet that will be
> + * attempted to be freed.
> + */
> +
> + /* Get last segment in most recently added packet. */
> + tx_last = sw_ring[txq->tx_tail].last_id;
> +
> + /* Get the next segment, which is the oldest segment in ring. */
> + tx_first = sw_ring[tx_last].next_id;
> +
> + /* Set the current index to the first. */
> + tx_id = tx_first;
> +
> + /*
> + * Loop through each packet. For each packet, verify that an
> + * mbuf exists and that the last segment is free. If so, free
> + * it and move on.
> + */
> + while (1) {
> + tx_last = sw_ring[tx_id].last_id;
> +
> + if (sw_ring[tx_last].mbuf) {
> + if (!(txr[tx_last].wb.status &
> + IXGBE_TXD_STAT_DD))
> + break;
> +
> + /* Get the start of the next packet. */
> + tx_next = sw_ring[tx_last].next_id;
> +
> + /*
> + * Loop through all segments in a
> + * packet.
> + */
> + do {
> + rte_pktmbuf_free_seg(sw_ring[tx_id].mbuf);
> + sw_ring[tx_id].mbuf = NULL;
> + sw_ring[tx_id].last_id = tx_id;
> +
> + /* Move to next segment. */
> + tx_id = sw_ring[tx_id].next_id;
> +
> + } while (tx_id != tx_next);
> +
> + /*
> + * Increment the number of packets
> + * freed.
> + */
> + count++;
> +
> + if (unlikely(count == (int)free_cnt))
> + break;
> + } else {
> + /*
> + * There are multiple reasons to be here:
> + * 1) All the packets on the ring have been
> + * freed - tx_id is equal to tx_first
> + * and some packets have been freed.
> + * - Done, exit
> + * 2) Interfaces has not sent a rings worth of
> + * packets yet, so the segment after tail is
> + * still empty. Or a previous call to this
> + * function freed some of the segments but
> + * not all so there is a hole in the list.
> + * Hopefully this is a rare case.
> + * - Walk the list and find the next mbuf. If
> + * there isn't one, then done.
> + */
> + if (likely(tx_id == tx_first && count != 0))
> + break;
> +
> + /*
> + * Walk the list and find the next mbuf, if any.
> + */
> + do {
> + /* Move to next segment. */
> + tx_id = sw_ring[tx_id].next_id;
> +
> + if (sw_ring[tx_id].mbuf)
> + break;
> +
> + } while (tx_id != tx_first);
> +
> + /*
> + * Determine why previous loop bailed. If there
> + * is not an mbuf, done.
> + */
> + if (sw_ring[tx_id].mbuf == NULL)
> + break;
> + }
> + }
> +
> + return count;
> +}
> +
> static void __attribute__((cold))
> ixgbe_tx_free_swring(struct ixgbe_tx_queue *txq)
> {
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.h b/drivers/net/ixgbe/ixgbe_rxtx.h
> index 505d344b9..2c3770af6 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.h
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.h
> @@ -285,6 +285,8 @@ int ixgbe_rx_vec_dev_conf_condition_check(struct
> rte_eth_dev *dev);
> int ixgbe_rxq_vec_setup(struct ixgbe_rx_queue *rxq);
> void ixgbe_rx_queue_release_mbufs_vec(struct ixgbe_rx_queue *rxq);
>
> +int ixgbe_tx_done_cleanup(void *txq, uint32_t free_cnt);
> +
> extern const uint32_t ptype_table[IXGBE_PACKET_TYPE_MAX];
> extern const uint32_t ptype_table_tn[IXGBE_PACKET_TYPE_TN_MAX];
>
> --
> 2.17.1
