[v3,2/2] net/virtio: on demand cleanup when in order xmit

Message ID 20190918170655.47669-2-yong.liu@intel.com
State Accepted
Delegated to: Maxime Coquelin
Headers show
Series
  • [v3,1/2] net/virtio: update stats when in order xmit done
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Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Liu, Yong Sept. 18, 2019, 5:06 p.m.
Check whether space are enough before burst enqueue operation. If more
space is needed, will try to clean up used descriptors for space on
demand. It can give more chances to free used descriptors, thus will
help RFC2544 performance. Also deduct failed xmit packets from total
xmit number.

Fixes: e5f456a98d3c ("net/virtio: support in-order Rx and Tx")
Cc: stable@dpdk.org

Signed-off-by: Marvin Liu <yong.liu@intel.com>

Comments

Maxime Coquelin Sept. 27, 2019, 9:02 a.m. | #1
On 9/18/19 7:06 PM, Marvin Liu wrote:
> Check whether space are enough before burst enqueue operation. If more
> space is needed, will try to clean up used descriptors for space on
> demand. It can give more chances to free used descriptors, thus will
> help RFC2544 performance. Also deduct failed xmit packets from total
> xmit number.
> 
> Fixes: e5f456a98d3c ("net/virtio: support in-order Rx and Tx")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Marvin Liu <yong.liu@intel.com>
> 
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime
Maxime Coquelin Sept. 27, 2019, 9:49 a.m. | #2
On 9/18/19 7:06 PM, Marvin Liu wrote:
> Check whether space are enough before burst enqueue operation. If more
> space is needed, will try to clean up used descriptors for space on
> demand. It can give more chances to free used descriptors, thus will
> help RFC2544 performance. Also deduct failed xmit packets from total
> xmit number.
> 
> Fixes: e5f456a98d3c ("net/virtio: support in-order Rx and Tx")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Marvin Liu <yong.liu@intel.com>

Applied to dpdk-next-virtio/master.

Thanks,
Maxime

Patch

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 91df5b1d0..7d5c60532 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -2152,6 +2152,22 @@  virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 	return nb_tx;
 }
 
+static __rte_always_inline int
+virtio_xmit_try_cleanup_inorder(struct virtqueue *vq, uint16_t need)
+{
+	uint16_t nb_used, nb_clean, nb_descs;
+	struct virtio_hw *hw = vq->hw;
+
+	nb_descs = vq->vq_free_cnt + need;
+	nb_used = VIRTQUEUE_NUSED(vq);
+	virtio_rmb(hw->weak_barriers);
+	nb_clean = RTE_MIN(need, (int)nb_used);
+
+	virtio_xmit_cleanup_inorder(vq, nb_clean);
+
+	return (nb_descs - vq->vq_free_cnt);
+}
+
 uint16_t
 virtio_xmit_pkts_inorder(void *tx_queue,
 			struct rte_mbuf **tx_pkts,
@@ -2161,8 +2177,9 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 	struct virtqueue *vq = txvq->vq;
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
-	uint16_t nb_used, nb_avail, nb_tx = 0, nb_inorder_pkts = 0;
+	uint16_t nb_used, nb_tx = 0, nb_inorder_pkts = 0;
 	struct rte_mbuf *inorder_pkts[nb_pkts];
+	int need;
 
 	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
 		return nb_tx;
@@ -2178,14 +2195,9 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 	if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
 		virtio_xmit_cleanup_inorder(vq, nb_used);
 
-	if (unlikely(!vq->vq_free_cnt))
-		virtio_xmit_cleanup_inorder(vq, nb_used);
-
-	nb_avail = RTE_MIN(vq->vq_free_cnt, nb_pkts);
-
-	for (nb_tx = 0; nb_tx < nb_avail; nb_tx++) {
+	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
-		int slots, need;
+		int slots;
 
 		/* optimize ring usage */
 		if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
@@ -2203,6 +2215,17 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 		}
 
 		if (nb_inorder_pkts) {
+			need = nb_inorder_pkts - vq->vq_free_cnt;
+			if (unlikely(need > 0)) {
+				need = virtio_xmit_try_cleanup_inorder(vq,
+								       need);
+				if (unlikely(need > 0)) {
+					PMD_TX_LOG(ERR,
+						"No free tx descriptors to "
+						"transmit");
+					break;
+				}
+			}
 			virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
 							nb_inorder_pkts);
 			nb_inorder_pkts = 0;
@@ -2211,13 +2234,7 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 		slots = txm->nb_segs + 1;
 		need = slots - vq->vq_free_cnt;
 		if (unlikely(need > 0)) {
-			nb_used = VIRTQUEUE_NUSED(vq);
-			virtio_rmb(hw->weak_barriers);
-			need = RTE_MIN(need, (int)nb_used);
-
-			virtio_xmit_cleanup_inorder(vq, need);
-
-			need = slots - vq->vq_free_cnt;
+			need = virtio_xmit_try_cleanup_inorder(vq, slots);
 
 			if (unlikely(need > 0)) {
 				PMD_TX_LOG(ERR,
@@ -2232,9 +2249,22 @@  virtio_xmit_pkts_inorder(void *tx_queue,
 	}
 
 	/* Transmit all inorder packets */
-	if (nb_inorder_pkts)
+	if (nb_inorder_pkts) {
+		need = nb_inorder_pkts - vq->vq_free_cnt;
+		if (unlikely(need > 0)) {
+			need = virtio_xmit_try_cleanup_inorder(vq,
+								  need);
+			if (unlikely(need > 0)) {
+				PMD_TX_LOG(ERR,
+					"No free tx descriptors to transmit");
+				nb_inorder_pkts = vq->vq_free_cnt;
+				nb_tx -= need;
+			}
+		}
+
 		virtqueue_enqueue_xmit_inorder(txvq, inorder_pkts,
 						nb_inorder_pkts);
+	}
 
 	txvq->stats.packets += nb_tx;