[dpdk-dev] [PATCH 0/3 v3] virtio: Tx performance improvements

[dpdk-dev] [PATCH 0/3 v3] virtio: Tx performance improvements

[Stephen Hemminger]

This patch series uses virtio negotiated features to allow for
more packets to be queued to host even though the default QEMU/KVM
virtio queue is very small 256 elements.

Stephen Hemminger (3):
  virtio: use indirect ring elements
  virtio: use any layout on transmit
  virtio: optimize transmit enqueue

 drivers/net/virtio/virtio_ethdev.c |  44 ++++++++----
 drivers/net/virtio/virtio_rxtx.c   | 133 ++++++++++++++++++++++++-------------
 drivers/net/virtio/virtqueue.h     |  19 ++++++
 3 files changed, 136 insertions(+), 60 deletions(-)

-- 
2.1.4

[dpdk-dev] [PATCH 1/3] virtio: use indirect ring elements

[Stephen Hemminger]

The virtio ring in QEMU/KVM is usually limited to 256 entries
and the normal way that virtio driver was queuing mbufs required
nsegs + 1 ring elements. By using the indirect ring element feature
if available, each packet will take only one ring slot even for
multi-segment packets.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/virtio/virtio_ethdev.c | 44 +++++++++++++++++-------
 drivers/net/virtio/virtio_rxtx.c   | 69 +++++++++++++++++++++++++++++---------
 drivers/net/virtio/virtqueue.h     | 19 +++++++++++
 3 files changed, 104 insertions(+), 28 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index caa970c..95c2203 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -387,27 +387,47 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
 	vq->virtio_net_hdr_mem = 0;
 
 	if (queue_type == VTNET_TQ) {
+		const struct rte_memzone *hdr_mz;
+		struct virtio_tx_region *txr;
+		unsigned int i;
+
 		/*
 		 * For each xmit packet, allocate a virtio_net_hdr
+		 * and indirect ring elements
 		 */
 		snprintf(vq_name, sizeof(vq_name), "port%d_tvq%d_hdrzone",
-			dev->data->port_id, queue_idx);
-		vq->virtio_net_hdr_mz = rte_memzone_reserve_aligned(vq_name,
-			vq_size * hw->vtnet_hdr_size,
-			socket_id, 0, RTE_CACHE_LINE_SIZE);
-		if (vq->virtio_net_hdr_mz == NULL) {
+			 dev->data->port_id, queue_idx);
+		hdr_mz = rte_memzone_reserve_aligned(vq_name,
+						     vq_size * sizeof(*txr),
+						     socket_id, 0,
+						     RTE_CACHE_LINE_SIZE);
+		if (hdr_mz == NULL) {
 			if (rte_errno == EEXIST)
-				vq->virtio_net_hdr_mz =
-					rte_memzone_lookup(vq_name);
-			if (vq->virtio_net_hdr_mz == NULL) {
+				hdr_mz = rte_memzone_lookup(vq_name);
+			if (hdr_mz == NULL) {
 				rte_free(vq);
 				return -ENOMEM;
 			}
 		}
-		vq->virtio_net_hdr_mem =
-			vq->virtio_net_hdr_mz->phys_addr;
-		memset(vq->virtio_net_hdr_mz->addr, 0,
-			vq_size * hw->vtnet_hdr_size);
+		vq->virtio_net_hdr_mz = hdr_mz;
+		vq->virtio_net_hdr_mem = hdr_mz->phys_addr;
+
+		txr = hdr_mz->addr;
+		memset(txr, 0, vq_size * sizeof(*txr));
+		for (i = 0; i < vq_size; i++) {
+			struct vring_desc *start_dp = txr[i].tx_indir;
+
+			vring_desc_init(start_dp, RTE_DIM(txr[i].tx_indir));
+
+			/* first indirect descriptor is always the tx header */
+			start_dp->addr = vq->virtio_net_hdr_mem
+				+ i * sizeof(*txr)
+				+ offsetof(struct virtio_tx_region, tx_hdr);
+
+			start_dp->len = vq->hw->vtnet_hdr_size;
+			start_dp->flags = VRING_DESC_F_NEXT;
+		}
+
 	} else if (queue_type == VTNET_CQ) {
 		/* Allocate a page for control vq command, data and status */
 		snprintf(vq_name, sizeof(vq_name), "port%d_cvq_hdrzone",
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index e96352c..5fe3eec 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -209,14 +209,15 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
 }
 
 static int
-virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
+virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
+		       int use_indirect)
 {
 	struct vq_desc_extra *dxp;
 	struct vring_desc *start_dp;
 	uint16_t seg_num = cookie->nb_segs;
-	uint16_t needed = 1 + seg_num;
+	uint16_t needed = use_indirect ? 1 : 1 + seg_num;
 	uint16_t head_idx, idx;
-	size_t head_size = txvq->hw->vtnet_hdr_size;
+	unsigned long offs;
 
 	if (unlikely(txvq->vq_free_cnt == 0))
 		return -ENOSPC;
@@ -232,10 +233,37 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
 	dxp->ndescs = needed;
 
 	start_dp = txvq->vq_ring.desc;
-	start_dp[idx].addr =
-		txvq->virtio_net_hdr_mem + idx * head_size;
-	start_dp[idx].len = head_size;
-	start_dp[idx].flags = VRING_DESC_F_NEXT;
+
+	if (use_indirect) {
+		/* setup tx ring slot to point to indirect
+		 * descriptor list stored in reserved region.
+		 *
+		 * the first slot in indirect ring is already preset
+		 * to point to the header in reserved region
+		 */
+		struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
+
+		offs = idx * sizeof(struct virtio_tx_region)
+			+ offsetof(struct virtio_tx_region, tx_indir);
+
+		start_dp[idx].addr  = txvq->virtio_net_hdr_mem + offs;
+		start_dp[idx].len   = (seg_num + 1) * sizeof(struct vring_desc);
+		start_dp[idx].flags = VRING_DESC_F_INDIRECT;
+
+		/* loop below will fill in rest of the indirect elements */
+		start_dp = txr[idx].tx_indir;
+		idx = 0;
+	} else {
+		/* setup first tx ring slot to point to header
+		 * stored in reserved region.
+		 */
+		offs = idx * sizeof(struct virtio_tx_region)
+			+ offsetof(struct virtio_tx_region, tx_hdr);
+
+		start_dp[idx].addr  = txvq->virtio_net_hdr_mem + offs;
+		start_dp[idx].len   = txvq->hw->vtnet_hdr_size;
+		start_dp[idx].flags = VRING_DESC_F_NEXT;
+	}
 
 	for (; ((seg_num > 0) && (cookie != NULL)); seg_num--) {
 		idx = start_dp[idx].next;
@@ -246,7 +274,12 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
 	}
 
 	start_dp[idx].flags &= ~VRING_DESC_F_NEXT;
-	idx = start_dp[idx].next;
+
+	if (use_indirect)
+		idx = txvq->vq_ring.desc[head_idx].next;
+	else
+		idx = start_dp[idx].next;
+
 	txvq->vq_desc_head_idx = idx;
 	if (txvq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
 		txvq->vq_desc_tail_idx = idx;
@@ -289,10 +322,7 @@ virtio_dev_vring_start(struct virtqueue *vq, int queue_type)
 	vq->vq_free_cnt = vq->vq_nentries;
 	memset(vq->vq_descx, 0, sizeof(struct vq_desc_extra) * vq->vq_nentries);
 
-	/* Chain all the descriptors in the ring with an END */
-	for (i = 0; i < size - 1; i++)
-		vr->desc[i].next = (uint16_t)(i + 1);
-	vr->desc[i].next = VQ_RING_DESC_CHAIN_END;
+	vring_desc_init(vr->desc, size);
 
 	/*
 	 * Disable device(host) interrupting guest
@@ -848,8 +878,15 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 
 	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
-		/* Need one more descriptor for virtio header. */
-		int need = txm->nb_segs - txvq->vq_free_cnt + 1;
+		int use_indirect, slots, need;
+
+		use_indirect = vtpci_with_feature(txvq->hw,
+						  VIRTIO_RING_F_INDIRECT_DESC)
+			&& (txm->nb_segs < VIRTIO_MAX_TX_INDIRECT);
+
+		/* How many main ring entries are needed to this Tx? */
+		slots = use_indirect ? 1 : 1 + txm->nb_segs;
+		need = slots - txvq->vq_free_cnt;
 
 		/* Positive value indicates it need free vring descriptors */
 		if (unlikely(need > 0)) {
@@ -858,7 +895,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 			need = RTE_MIN(need, (int)nb_used);
 
 			virtio_xmit_cleanup(txvq, need);
-			need = txm->nb_segs - txvq->vq_free_cnt + 1;
+			need = slots - txvq->vq_free_cnt;
 			if (unlikely(need > 0)) {
 				PMD_TX_LOG(ERR,
 					   "No free tx descriptors to transmit");
@@ -876,7 +913,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		}
 
 		/* Enqueue Packet buffers */
-		error = virtqueue_enqueue_xmit(txvq, txm);
+		error = virtqueue_enqueue_xmit(txvq, txm, use_indirect);
 		if (unlikely(error)) {
 			if (error == ENOSPC)
 				PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 68e0b4b..4e9239e 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -243,6 +243,25 @@ struct virtio_net_hdr_mrg_rxbuf {
 	uint16_t num_buffers; /**< Number of merged rx buffers */
 };
 
+/* Region reserved to allow for transmit header and indirect ring */
+#define VIRTIO_MAX_TX_INDIRECT 8
+struct virtio_tx_region {
+	struct virtio_net_hdr_mrg_rxbuf tx_hdr;
+	struct vring_desc tx_indir[VIRTIO_MAX_TX_INDIRECT]
+			   __attribute__((__aligned__(16)));
+};
+
+/* Chain all the descriptors in the ring with an END */
+static inline void
+vring_desc_init(struct vring_desc *dp, uint16_t n)
+{
+	uint16_t i;
+
+	for (i = 0; i < n - 1; i++)
+		dp[i].next = (uint16_t)(i + 1);
+	dp[i].next = VQ_RING_DESC_CHAIN_END;
+}
+
 /**
  * Tell the backend not to interrupt us.
  */
-- 
2.1.4

[dpdk-dev] [PATCH 2/3] virtio: use any layout on transmit

[Stephen Hemminger]

Virtio supports a feature that allows sender to put transmit
header prepended to data.  It requires that the mbuf be writeable, correct
alignment, and the feature has been negotiatied.  If all this works out,
then it will be the optimum way to transmit a single segment packet.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/virtio/virtio_rxtx.c | 73 +++++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 27 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 5fe3eec..0f12e64 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -210,13 +210,13 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
 
 static int
 virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
-		       int use_indirect)
+		       uint16_t needed, int use_indirect, int can_push)
 {
 	struct vq_desc_extra *dxp;
 	struct vring_desc *start_dp;
 	uint16_t seg_num = cookie->nb_segs;
-	uint16_t needed = use_indirect ? 1 : 1 + seg_num;
 	uint16_t head_idx, idx;
+	uint16_t head_size = txvq->hw->vtnet_hdr_size;
 	unsigned long offs;
 
 	if (unlikely(txvq->vq_free_cnt == 0))
@@ -234,7 +234,12 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
 
 	start_dp = txvq->vq_ring.desc;
 
-	if (use_indirect) {
+	if (can_push) {
+		/* put on zero'd transmit header (no offloads) */
+		void *hdr = rte_pktmbuf_prepend(cookie, head_size);
+
+		memset(hdr, 0, head_size);
+	} else if (use_indirect) {
 		/* setup tx ring slot to point to indirect
 		 * descriptor list stored in reserved region.
 		 *
@@ -252,7 +257,7 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
 
 		/* loop below will fill in rest of the indirect elements */
 		start_dp = txr[idx].tx_indir;
-		idx = 0;
+		idx = 1;
 	} else {
 		/* setup first tx ring slot to point to header
 		 * stored in reserved region.
@@ -263,22 +268,20 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
 		start_dp[idx].addr  = txvq->virtio_net_hdr_mem + offs;
 		start_dp[idx].len   = txvq->hw->vtnet_hdr_size;
 		start_dp[idx].flags = VRING_DESC_F_NEXT;
+		idx = start_dp[idx].next;
 	}
 
-	for (; ((seg_num > 0) && (cookie != NULL)); seg_num--) {
-		idx = start_dp[idx].next;
+	do {
 		start_dp[idx].addr  = rte_mbuf_data_dma_addr(cookie);
 		start_dp[idx].len   = cookie->data_len;
-		start_dp[idx].flags = VRING_DESC_F_NEXT;
-		cookie = cookie->next;
-	}
+		start_dp[idx].flags = cookie->next ? VRING_DESC_F_NEXT : 0;
+		idx = start_dp[idx].next;
+	} while ((cookie = cookie->next) != NULL);
 
 	start_dp[idx].flags &= ~VRING_DESC_F_NEXT;
 
 	if (use_indirect)
 		idx = txvq->vq_ring.desc[head_idx].next;
-	else
-		idx = start_dp[idx].next;
 
 	txvq->vq_desc_head_idx = idx;
 	if (txvq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
@@ -859,10 +862,13 @@ virtio_recv_mergeable_pkts(void *rx_queue,
 	return nb_rx;
 }
 
+
 uint16_t
 virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
 	struct virtqueue *txvq = tx_queue;
+	struct virtio_hw *hw = txvq->hw;
+	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_used, nb_tx;
 	int error;
 
@@ -878,14 +884,35 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 
 	for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
 		struct rte_mbuf *txm = tx_pkts[nb_tx];
-		int use_indirect, slots, need;
+		int can_push = 0, use_indirect = 0, slots, need;
 
-		use_indirect = vtpci_with_feature(txvq->hw,
-						  VIRTIO_RING_F_INDIRECT_DESC)
-			&& (txm->nb_segs < VIRTIO_MAX_TX_INDIRECT);
+		/* Do VLAN tag insertion */
+		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
+			error = rte_vlan_insert(&txm);
+			if (unlikely(error)) {
+				rte_pktmbuf_free(txm);
+				continue;
+			}
+		}
 
-		/* How many main ring entries are needed to this Tx? */
-		slots = use_indirect ? 1 : 1 + txm->nb_segs;
+		/* optimize ring usage */
+		if (vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) &&
+		    rte_mbuf_refcnt_read(txm) == 1 &&
+		    txm->nb_segs == 1 &&
+		    rte_pktmbuf_headroom(txm) >= hdr_size &&
+		    rte_is_aligned(rte_pktmbuf_mtod(txm, char *),
+				   __alignof__(struct virtio_net_hdr_mrg_rxbuf)))
+			can_push = 1;
+		else if (vtpci_with_feature(hw, VIRTIO_RING_F_INDIRECT_DESC) &&
+			 txm->nb_segs < VIRTIO_MAX_TX_INDIRECT)
+			use_indirect = 1;
+
+		/* How many main ring entries are needed to this Tx?
+		 * any_layout => number of segments
+		 * indirect   => 1
+		 * default    => number of segments + 1
+		 */
+		slots = use_indirect ? 1 : (txm->nb_segs + !can_push);
 		need = slots - txvq->vq_free_cnt;
 
 		/* Positive value indicates it need free vring descriptors */
@@ -903,17 +930,9 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 			}
 		}
 
-		/* Do VLAN tag insertion */
-		if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
-			error = rte_vlan_insert(&txm);
-			if (unlikely(error)) {
-				rte_pktmbuf_free(txm);
-				continue;
-			}
-		}
-
 		/* Enqueue Packet buffers */
-		error = virtqueue_enqueue_xmit(txvq, txm, use_indirect);
+		error = virtqueue_enqueue_xmit(txvq, txm, slots,
+					       use_indirect, can_push);
 		if (unlikely(error)) {
 			if (error == ENOSPC)
 				PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
-- 
2.1.4

[dpdk-dev] [PATCH 3/3] virtio: optimize transmit enqueue

[Stephen Hemminger]

All the error checks in virtqueue_enqueue_xmit are already done
by the caller. Therefore they can be removed to improve performance.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/virtio/virtio_rxtx.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 0f12e64..1c0b6eb 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -208,7 +208,7 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
 	return 0;
 }
 
-static int
+static inline void
 virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
 		       uint16_t needed, int use_indirect, int can_push)
 {
@@ -219,14 +219,7 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
 	uint16_t head_size = txvq->hw->vtnet_hdr_size;
 	unsigned long offs;
 
-	if (unlikely(txvq->vq_free_cnt == 0))
-		return -ENOSPC;
-	if (unlikely(txvq->vq_free_cnt < needed))
-		return -EMSGSIZE;
 	head_idx = txvq->vq_desc_head_idx;
-	if (unlikely(head_idx >= txvq->vq_nentries))
-		return -EFAULT;
-
 	idx = head_idx;
 	dxp = &txvq->vq_descx[idx];
 	dxp->cookie = (void *)cookie;
@@ -288,8 +281,6 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
 		txvq->vq_desc_tail_idx = idx;
 	txvq->vq_free_cnt = (uint16_t)(txvq->vq_free_cnt - needed);
 	vq_update_avail_ring(txvq, head_idx);
-
-	return 0;
 }
 
 static inline struct rte_mbuf *
@@ -931,17 +922,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		}
 
 		/* Enqueue Packet buffers */
-		error = virtqueue_enqueue_xmit(txvq, txm, slots,
-					       use_indirect, can_push);
-		if (unlikely(error)) {
-			if (error == ENOSPC)
-				PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
-			else if (error == EMSGSIZE)
-				PMD_TX_LOG(ERR, "virtqueue_enqueue Free count < 1");
-			else
-				PMD_TX_LOG(ERR, "virtqueue_enqueue error: %d", error);
-			break;
-		}
+		virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect, can_push);
 
 		txvq->bytes += txm->pkt_len;
 		virtio_update_packet_stats(txvq, txm);
-- 
2.1.4

Re: [dpdk-dev] [PATCH 0/3 v3] virtio: Tx performance improvements

[Bruce Richardson]

On Fri, Mar 04, 2016 at 10:19:18AM -0800, Stephen Hemminger wrote:
> This patch series uses virtio negotiated features to allow for
> more packets to be queued to host even though the default QEMU/KVM
> virtio queue is very small 256 elements.
> 
> Stephen Hemminger (3):
>   virtio: use indirect ring elements
>   virtio: use any layout on transmit
>   virtio: optimize transmit enqueue
> 
These patches require an ack to merge. Virtio maintainers, can you please
review and ack if ok.

/Bruce

Re: [dpdk-dev] [PATCH 0/3 v3] virtio: Tx performance improvements

[Yuanhan Liu]

On Mon, Mar 14, 2016 at 10:56:27AM +0000, Bruce Richardson wrote:
> On Fri, Mar 04, 2016 at 10:19:18AM -0800, Stephen Hemminger wrote:
> > This patch series uses virtio negotiated features to allow for
> > more packets to be queued to host even though the default QEMU/KVM
> > virtio queue is very small 256 elements.
> > 
> > Stephen Hemminger (3):
> >   virtio: use indirect ring elements
> >   virtio: use any layout on transmit
> >   virtio: optimize transmit enqueue
> > 
> These patches require an ack to merge. Virtio maintainers, can you please
> review and ack if ok.

Thomas meant to merge this set in last release. It was delayed due to a
build error. So, I think it's okay to merge it.

Anyway, here is mine:

Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

	--yliu

Re: [dpdk-dev] [PATCH 0/3 v3] virtio: Tx performance improvements

[Xie, Huawei]

On 3/14/2016 6:56 PM, Richardson, Bruce wrote:
> On Fri, Mar 04, 2016 at 10:19:18AM -0800, Stephen Hemminger wrote:
>> This patch series uses virtio negotiated features to allow for
>> more packets to be queued to host even though the default QEMU/KVM
>> virtio queue is very small 256 elements.
>>
>> Stephen Hemminger (3):
>>   virtio: use indirect ring elements
>>   virtio: use any layout on transmit
>>   virtio: optimize transmit enqueue
>>
> These patches require an ack to merge. Virtio maintainers, can you please
> review and ack if ok.
>
> /Bruce
>
Acked in the previous release window.

Acked-by: Huawei Xie <huawei.xie@intel.com>

Re: [dpdk-dev] [PATCH 0/3 v3] virtio: Tx performance improvements

[Bruce Richardson]

On Wed, Mar 16, 2016 at 08:25:08AM +0000, Xie, Huawei wrote:
> On 3/14/2016 6:56 PM, Richardson, Bruce wrote:
> > On Fri, Mar 04, 2016 at 10:19:18AM -0800, Stephen Hemminger wrote:
> >> This patch series uses virtio negotiated features to allow for
> >> more packets to be queued to host even though the default QEMU/KVM
> >> virtio queue is very small 256 elements.
> >>
> >> Stephen Hemminger (3):
> >>   virtio: use indirect ring elements
> >>   virtio: use any layout on transmit
> >>   virtio: optimize transmit enqueue
> >>
> > These patches require an ack to merge. Virtio maintainers, can you please
> > review and ack if ok.
> >
> > /Bruce
> >
> Acked in the previous release window.
> 
> Acked-by: Huawei Xie <huawei.xie@intel.com>
> 
Pushed to dpdk-next-net/rel_16_04

/Bruce