[dpdk-dev] [PATCH v4 0/4] net/virtio: make virtqueue struct cache-friendly

[dpdk-dev] [PATCH v4 0/4] net/virtio: make virtqueue struct cache-friendly

[Maxime Coquelin]

This series optimizes the cache usage of virtqueue struct,
by making a "fake" mbuf being dynamically allocated in Rx
virtnet struct, by removing a useless virtuque pointer
into the virtnet structs and by moving a few fields
to pack holes.

With these 3 patches, the virtqueue struct size goes from
576 bytes (9 cachelines) to 248 bytes (4 cachelines).

Changes in v4:
==============
- Fix ARM build failure after rebase (0-day robot)
- Fix fake_mbuf freeing (David)
- Applied David R-by

Changes in v3:
==============
- Use rte_zmalloc_socket for fake mbuf alloc (David)
- Fix typos in commit messages
- Remove superfluous pointer check befor freeing (David)
- Fix checkpatch warnings

Changes in v2:
==============
- Rebase on latest main
- Improve error path in virtio_init_queue
- Fix various typos in commit messages

Maxime Coquelin (4):
  net/virtio: remove reference to virtqueue in vrings
  net/virtio: improve queue init error path
  net/virtio: allocate fake mbuf in Rx queue
  net/virtio: pack virtqueue struct

 drivers/net/virtio/virtio_ethdev.c            | 64 +++++++++++--------
 drivers/net/virtio/virtio_rxtx.c              | 37 +++++------
 drivers/net/virtio/virtio_rxtx.h              |  5 +-
 drivers/net/virtio/virtio_rxtx_packed.c       |  4 +-
 drivers/net/virtio/virtio_rxtx_packed.h       |  6 +-
 drivers/net/virtio/virtio_rxtx_packed_avx.h   |  4 +-
 drivers/net/virtio/virtio_rxtx_packed_neon.h  |  4 +-
 drivers/net/virtio/virtio_rxtx_simple.h       |  2 +-
 .../net/virtio/virtio_rxtx_simple_altivec.c   |  2 +-
 drivers/net/virtio/virtio_rxtx_simple_neon.c  |  2 +-
 drivers/net/virtio/virtio_rxtx_simple_sse.c   |  2 +-
 .../net/virtio/virtio_user/virtio_user_dev.c  |  4 +-
 drivers/net/virtio/virtio_user_ethdev.c       |  2 +-
 drivers/net/virtio/virtqueue.h                | 24 ++++---
 14 files changed, 87 insertions(+), 75 deletions(-)

-- 
2.29.2

[dpdk-dev] [PATCH v4 1/4] net/virtio: remove reference to virtqueue in vrings

[Maxime Coquelin]

Vrings are part of the virtqueues, so we don't need
to have a pointer to it in Vrings descriptions.

Instead, let's just subtract from its offset to
calculate virtqueue address.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c            | 36 +++++++++----------
 drivers/net/virtio/virtio_rxtx.c              | 28 +++++++--------
 drivers/net/virtio/virtio_rxtx.h              |  3 --
 drivers/net/virtio/virtio_rxtx_packed.c       |  4 +--
 drivers/net/virtio/virtio_rxtx_packed.h       |  6 ++--
 drivers/net/virtio/virtio_rxtx_packed_avx.h   |  4 +--
 drivers/net/virtio/virtio_rxtx_packed_neon.h  |  4 +--
 drivers/net/virtio/virtio_rxtx_simple.h       |  2 +-
 .../net/virtio/virtio_rxtx_simple_altivec.c   |  2 +-
 drivers/net/virtio/virtio_rxtx_simple_neon.c  |  2 +-
 drivers/net/virtio/virtio_rxtx_simple_sse.c   |  2 +-
 .../net/virtio/virtio_user/virtio_user_dev.c  |  4 +--
 drivers/net/virtio/virtio_user_ethdev.c       |  2 +-
 drivers/net/virtio/virtqueue.h                |  6 +++-
 14 files changed, 51 insertions(+), 54 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 333a5243a9..af090fdf9c 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -133,7 +133,7 @@ virtio_send_command_packed(struct virtnet_ctl *cvq,
 			   struct virtio_pmd_ctrl *ctrl,
 			   int *dlen, int pkt_num)
 {
-	struct virtqueue *vq = cvq->vq;
+	struct virtqueue *vq = virtnet_cq_to_vq(cvq);
 	int head;
 	struct vring_packed_desc *desc = vq->vq_packed.ring.desc;
 	struct virtio_pmd_ctrl *result;
@@ -229,7 +229,7 @@ virtio_send_command_split(struct virtnet_ctl *cvq,
 			  int *dlen, int pkt_num)
 {
 	struct virtio_pmd_ctrl *result;
-	struct virtqueue *vq = cvq->vq;
+	struct virtqueue *vq = virtnet_cq_to_vq(cvq);
 	uint32_t head, i;
 	int k, sum = 0;
 
@@ -316,13 +316,13 @@ virtio_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 
 	ctrl->status = status;
 
-	if (!cvq || !cvq->vq) {
+	if (!cvq) {
 		PMD_INIT_LOG(ERR, "Control queue is not supported.");
 		return -1;
 	}
 
 	rte_spinlock_lock(&cvq->lock);
-	vq = cvq->vq;
+	vq = virtnet_cq_to_vq(cvq);
 
 	PMD_INIT_LOG(DEBUG, "vq->vq_desc_head_idx = %d, status = %d, "
 		"vq->hw->cvq = %p vq = %p",
@@ -552,19 +552,16 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 
 		vq->sw_ring = sw_ring;
 		rxvq = &vq->rxq;
-		rxvq->vq = vq;
 		rxvq->port_id = dev->data->port_id;
 		rxvq->mz = mz;
 	} else if (queue_type == VTNET_TQ) {
 		txvq = &vq->txq;
-		txvq->vq = vq;
 		txvq->port_id = dev->data->port_id;
 		txvq->mz = mz;
 		txvq->virtio_net_hdr_mz = hdr_mz;
 		txvq->virtio_net_hdr_mem = hdr_mz->iova;
 	} else if (queue_type == VTNET_CQ) {
 		cvq = &vq->cq;
-		cvq->vq = vq;
 		cvq->mz = mz;
 		cvq->virtio_net_hdr_mz = hdr_mz;
 		cvq->virtio_net_hdr_mem = hdr_mz->iova;
@@ -851,7 +848,7 @@ virtio_dev_rx_queue_intr_enable(struct rte_eth_dev *dev, uint16_t queue_id)
 {
 	struct virtio_hw *hw = dev->data->dev_private;
 	struct virtnet_rx *rxvq = dev->data->rx_queues[queue_id];
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 
 	virtqueue_enable_intr(vq);
 	virtio_mb(hw->weak_barriers);
@@ -862,7 +859,7 @@ static int
 virtio_dev_rx_queue_intr_disable(struct rte_eth_dev *dev, uint16_t queue_id)
 {
 	struct virtnet_rx *rxvq = dev->data->rx_queues[queue_id];
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 
 	virtqueue_disable_intr(vq);
 	return 0;
@@ -2180,8 +2177,7 @@ static int
 virtio_dev_start(struct rte_eth_dev *dev)
 {
 	uint16_t nb_queues, i;
-	struct virtnet_rx *rxvq;
-	struct virtnet_tx *txvq __rte_unused;
+	struct virtqueue *vq;
 	struct virtio_hw *hw = dev->data->dev_private;
 	int ret;
 
@@ -2238,27 +2234,27 @@ virtio_dev_start(struct rte_eth_dev *dev)
 	PMD_INIT_LOG(DEBUG, "nb_queues=%d", nb_queues);
 
 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
-		rxvq = dev->data->rx_queues[i];
+		vq = virtnet_rxq_to_vq(dev->data->rx_queues[i]);
 		/* Flush the old packets */
-		virtqueue_rxvq_flush(rxvq->vq);
-		virtqueue_notify(rxvq->vq);
+		virtqueue_rxvq_flush(vq);
+		virtqueue_notify(vq);
 	}
 
 	for (i = 0; i < dev->data->nb_tx_queues; i++) {
-		txvq = dev->data->tx_queues[i];
-		virtqueue_notify(txvq->vq);
+		vq = virtnet_txq_to_vq(dev->data->tx_queues[i]);
+		virtqueue_notify(vq);
 	}
 
 	PMD_INIT_LOG(DEBUG, "Notified backend at initialization");
 
 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
-		rxvq = dev->data->rx_queues[i];
-		VIRTQUEUE_DUMP(rxvq->vq);
+		vq = virtnet_rxq_to_vq(dev->data->rx_queues[i]);
+		VIRTQUEUE_DUMP(vq);
 	}
 
 	for (i = 0; i < dev->data->nb_tx_queues; i++) {
-		txvq = dev->data->tx_queues[i];
-		VIRTQUEUE_DUMP(txvq->vq);
+		vq = virtnet_txq_to_vq(dev->data->tx_queues[i]);
+		VIRTQUEUE_DUMP(vq);
 	}
 
 	set_rxtx_funcs(dev);
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 40283001b0..32af8d3d11 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -43,7 +43,7 @@ int
 virtio_dev_rx_queue_done(void *rxq, uint16_t offset)
 {
 	struct virtnet_rx *rxvq = rxq;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 
 	return virtqueue_nused(vq) >= offset;
 }
@@ -424,7 +424,7 @@ virtqueue_enqueue_xmit_inorder(struct virtnet_tx *txvq,
 			uint16_t num)
 {
 	struct vq_desc_extra *dxp;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct vring_desc *start_dp;
 	struct virtio_net_hdr *hdr;
 	uint16_t idx;
@@ -470,7 +470,7 @@ virtqueue_enqueue_xmit_packed_fast(struct virtnet_tx *txvq,
 				   struct rte_mbuf *cookie,
 				   int in_order)
 {
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct vring_packed_desc *dp;
 	struct vq_desc_extra *dxp;
 	uint16_t idx, id, flags;
@@ -524,7 +524,7 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 {
 	struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
 	struct vq_desc_extra *dxp;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct vring_desc *start_dp;
 	uint16_t seg_num = cookie->nb_segs;
 	uint16_t head_idx, idx;
@@ -614,9 +614,9 @@ virtio_dev_cq_start(struct rte_eth_dev *dev)
 {
 	struct virtio_hw *hw = dev->data->dev_private;
 
-	if (hw->cvq && hw->cvq->vq) {
+	if (hw->cvq) {
 		rte_spinlock_init(&hw->cvq->lock);
-		VIRTQUEUE_DUMP((struct virtqueue *)hw->cvq->vq);
+		VIRTQUEUE_DUMP(virtnet_cq_to_vq(hw->cvq));
 	}
 }
 
@@ -948,7 +948,7 @@ uint16_t
 virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	struct rte_mbuf *rxm;
 	uint16_t nb_used, num, nb_rx;
@@ -1055,7 +1055,7 @@ virtio_recv_pkts_packed(void *rx_queue, struct rte_mbuf **rx_pkts,
 			uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	struct rte_mbuf *rxm;
 	uint16_t num, nb_rx;
@@ -1158,7 +1158,7 @@ virtio_recv_pkts_inorder(void *rx_queue,
 			uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	struct rte_mbuf *rxm;
 	struct rte_mbuf *prev = NULL;
@@ -1342,7 +1342,7 @@ virtio_recv_mergeable_pkts(void *rx_queue,
 			uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	struct rte_mbuf *rxm;
 	struct rte_mbuf *prev = NULL;
@@ -1520,7 +1520,7 @@ virtio_recv_mergeable_pkts_packed(void *rx_queue,
 			uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	struct rte_mbuf *rxm;
 	struct rte_mbuf *prev = NULL;
@@ -1731,7 +1731,7 @@ virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf **tx_pkts,
 			uint16_t nb_pkts)
 {
 	struct virtnet_tx *txvq = tx_queue;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_tx = 0;
@@ -1812,7 +1812,7 @@ uint16_t
 virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
 	struct virtnet_tx *txvq = tx_queue;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_used, nb_tx = 0;
@@ -1912,7 +1912,7 @@ virtio_xmit_pkts_inorder(void *tx_queue,
 			uint16_t nb_pkts)
 {
 	struct virtnet_tx *txvq = tx_queue;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t nb_used, nb_tx = 0, nb_inorder_pkts = 0;
diff --git a/drivers/net/virtio/virtio_rxtx.h b/drivers/net/virtio/virtio_rxtx.h
index 1eb8dae227..7f1036be6f 100644
--- a/drivers/net/virtio/virtio_rxtx.h
+++ b/drivers/net/virtio/virtio_rxtx.h
@@ -18,7 +18,6 @@ struct virtnet_stats {
 };
 
 struct virtnet_rx {
-	struct virtqueue *vq;
 	/* dummy mbuf, for wraparound when processing RX ring. */
 	struct rte_mbuf fake_mbuf;
 	uint64_t mbuf_initializer; /**< value to init mbufs. */
@@ -34,7 +33,6 @@ struct virtnet_rx {
 };
 
 struct virtnet_tx {
-	struct virtqueue *vq;
 	/**< memzone to populate hdr. */
 	const struct rte_memzone *virtio_net_hdr_mz;
 	rte_iova_t virtio_net_hdr_mem;   /**< hdr for each xmit packet */
@@ -49,7 +47,6 @@ struct virtnet_tx {
 };
 
 struct virtnet_ctl {
-	struct virtqueue *vq;
 	/**< memzone to populate hdr. */
 	const struct rte_memzone *virtio_net_hdr_mz;
 	rte_iova_t virtio_net_hdr_mem;  /**< hdr for each xmit packet */
diff --git a/drivers/net/virtio/virtio_rxtx_packed.c b/drivers/net/virtio/virtio_rxtx_packed.c
index 882dca36ec..ab489a58af 100644
--- a/drivers/net/virtio/virtio_rxtx_packed.c
+++ b/drivers/net/virtio/virtio_rxtx_packed.c
@@ -27,7 +27,7 @@ virtio_xmit_pkts_packed_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
 			uint16_t nb_pkts)
 {
 	struct virtnet_tx *txvq = tx_queue;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t nb_tx = 0;
 	uint16_t remained;
@@ -81,7 +81,7 @@ virtio_recv_pkts_packed_vec(void *rx_queue,
 			    uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t num, nb_rx = 0;
 	uint32_t nb_enqueued = 0;
diff --git a/drivers/net/virtio/virtio_rxtx_packed.h b/drivers/net/virtio/virtio_rxtx_packed.h
index 3037c8c871..1d1db60da8 100644
--- a/drivers/net/virtio/virtio_rxtx_packed.h
+++ b/drivers/net/virtio/virtio_rxtx_packed.h
@@ -104,7 +104,7 @@ static inline int
 virtqueue_enqueue_single_packed_vec(struct virtnet_tx *txvq,
 				    struct rte_mbuf *txm)
 {
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint16_t slots, can_push = 0, use_indirect = 0;
@@ -212,7 +212,7 @@ virtqueue_dequeue_single_packed_vec(struct virtnet_rx *rxvq,
 {
 	uint16_t used_idx, id;
 	uint32_t len;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint32_t hdr_size = hw->vtnet_hdr_size;
 	struct virtio_net_hdr *hdr;
@@ -264,7 +264,7 @@ virtio_recv_refill_packed_vec(struct virtnet_rx *rxvq,
 			      struct rte_mbuf **cookie,
 			      uint16_t num)
 {
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct vring_packed_desc *start_dp = vq->vq_packed.ring.desc;
 	uint16_t flags = vq->vq_packed.cached_flags;
 	struct virtio_hw *hw = vq->hw;
diff --git a/drivers/net/virtio/virtio_rxtx_packed_avx.h b/drivers/net/virtio/virtio_rxtx_packed_avx.h
index 49e845d02a..228cf5437b 100644
--- a/drivers/net/virtio/virtio_rxtx_packed_avx.h
+++ b/drivers/net/virtio/virtio_rxtx_packed_avx.h
@@ -20,7 +20,7 @@ static inline int
 virtqueue_enqueue_batch_packed_vec(struct virtnet_tx *txvq,
 				   struct rte_mbuf **tx_pkts)
 {
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	uint16_t head_size = vq->hw->vtnet_hdr_size;
 	uint16_t idx = vq->vq_avail_idx;
 	struct virtio_net_hdr *hdr;
@@ -142,7 +142,7 @@ static inline uint16_t
 virtqueue_dequeue_batch_packed_vec(struct virtnet_rx *rxvq,
 				   struct rte_mbuf **rx_pkts)
 {
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t hdr_size = hw->vtnet_hdr_size;
 	uint64_t addrs[PACKED_BATCH_SIZE];
diff --git a/drivers/net/virtio/virtio_rxtx_packed_neon.h b/drivers/net/virtio/virtio_rxtx_packed_neon.h
index 851c81f312..d4257e68f0 100644
--- a/drivers/net/virtio/virtio_rxtx_packed_neon.h
+++ b/drivers/net/virtio/virtio_rxtx_packed_neon.h
@@ -20,7 +20,7 @@ static inline int
 virtqueue_enqueue_batch_packed_vec(struct virtnet_tx *txvq,
 				   struct rte_mbuf **tx_pkts)
 {
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	uint16_t head_size = vq->hw->vtnet_hdr_size;
 	uint16_t idx = vq->vq_avail_idx;
 	struct virtio_net_hdr *hdr;
@@ -163,7 +163,7 @@ static inline int
 virtqueue_dequeue_batch_packed_vec(struct virtnet_rx *rxvq,
 				   struct rte_mbuf **rx_pkts)
 {
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t head_size = hw->vtnet_hdr_size;
 	uint16_t id = vq->vq_used_cons_idx;
diff --git a/drivers/net/virtio/virtio_rxtx_simple.h b/drivers/net/virtio/virtio_rxtx_simple.h
index f2a5aedf97..f258771fcf 100644
--- a/drivers/net/virtio/virtio_rxtx_simple.h
+++ b/drivers/net/virtio/virtio_rxtx_simple.h
@@ -23,7 +23,7 @@ virtio_rxq_rearm_vec(struct virtnet_rx *rxvq)
 	struct rte_mbuf **sw_ring;
 	struct vring_desc *start_dp;
 	int ret;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 
 	desc_idx = vq->vq_avail_idx & (vq->vq_nentries - 1);
 	sw_ring = &vq->sw_ring[desc_idx];
diff --git a/drivers/net/virtio/virtio_rxtx_simple_altivec.c b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
index f09a1eda49..62e5100a48 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_altivec.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_altivec.c
@@ -41,7 +41,7 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t nb_used, nb_total;
 	uint16_t desc_idx;
diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c b/drivers/net/virtio/virtio_rxtx_simple_neon.c
index 2cba800807..c8e4b13a02 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
@@ -41,7 +41,7 @@ virtio_recv_pkts_vec(void *rx_queue,
 		uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t nb_used, nb_total;
 	uint16_t desc_idx;
diff --git a/drivers/net/virtio/virtio_rxtx_simple_sse.c b/drivers/net/virtio/virtio_rxtx_simple_sse.c
index 85a5a6664a..ff4eba33d6 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_sse.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_sse.c
@@ -41,7 +41,7 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
 	uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
-	struct virtqueue *vq = rxvq->vq;
+	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
 	struct virtio_hw *hw = vq->hw;
 	uint16_t nb_used, nb_total;
 	uint16_t desc_idx;
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 1b54d55bd8..446837b1fd 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -871,13 +871,13 @@ virtio_user_dev_reset_queues_packed(struct rte_eth_dev *eth_dev)
 	/* Vring reset for each Tx queue and Rx queue. */
 	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
 		rxvq = eth_dev->data->rx_queues[i];
-		virtqueue_rxvq_reset_packed(rxvq->vq);
+		virtqueue_rxvq_reset_packed(virtnet_rxq_to_vq(rxvq));
 		virtio_dev_rx_queue_setup_finish(eth_dev, i);
 	}
 
 	for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
 		txvq = eth_dev->data->tx_queues[i];
-		virtqueue_txvq_reset_packed(txvq->vq);
+		virtqueue_txvq_reset_packed(virtnet_txq_to_vq(txvq));
 	}
 
 	hw->started = 1;
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index 1810a54694..9314ca5204 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -249,7 +249,7 @@ virtio_user_notify_queue(struct virtio_hw *hw, struct virtqueue *vq)
 	uint64_t buf = 1;
 	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
 
-	if (hw->cvq && (hw->cvq->vq == vq)) {
+	if (hw->cvq && (virtnet_cq_to_vq(hw->cvq) == vq)) {
 		if (virtio_with_packed_queue(vq->hw))
 			virtio_user_handle_cq_packed(dev, vq->vq_queue_index);
 		else
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 71b66f3208..17e76f0e8c 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -217,6 +217,10 @@ struct vq_desc_extra {
 	uint16_t next;
 };
 
+#define virtnet_rxq_to_vq(rxvq) container_of(rxvq, struct virtqueue, rxq)
+#define virtnet_txq_to_vq(txvq) container_of(txvq, struct virtqueue, txq)
+#define virtnet_cq_to_vq(cvq) container_of(cvq, struct virtqueue, cq)
+
 struct virtqueue {
 	struct virtio_hw  *hw; /**< virtio_hw structure pointer. */
 	union {
@@ -667,7 +671,7 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 {
 	struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
 	struct vq_desc_extra *dxp;
-	struct virtqueue *vq = txvq->vq;
+	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
 	struct vring_packed_desc *start_dp, *head_dp;
 	uint16_t idx, id, head_idx, head_flags;
 	int16_t head_size = vq->hw->vtnet_hdr_size;
-- 
2.29.2

[dpdk-dev] [PATCH v4 2/4] net/virtio: improve queue init error path

[Maxime Coquelin]

This patch improves the error path of virtio_init_queue(),
by cleaning in reversing order all resources that have
been allocated.

Suggested-by: Chenbo Xia <chenbo.xia@intel.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index af090fdf9c..d5643733f7 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -507,7 +507,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 			mz = rte_memzone_lookup(vq_name);
 		if (mz == NULL) {
 			ret = -ENOMEM;
-			goto fail_q_alloc;
+			goto free_vq;
 		}
 	}
 
@@ -533,7 +533,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 				hdr_mz = rte_memzone_lookup(vq_hdr_name);
 			if (hdr_mz == NULL) {
 				ret = -ENOMEM;
-				goto fail_q_alloc;
+				goto free_mz;
 			}
 		}
 	}
@@ -547,7 +547,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 		if (!sw_ring) {
 			PMD_INIT_LOG(ERR, "can not allocate RX soft ring");
 			ret = -ENOMEM;
-			goto fail_q_alloc;
+			goto free_hdr_mz;
 		}
 
 		vq->sw_ring = sw_ring;
@@ -604,15 +604,20 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 
 	if (VIRTIO_OPS(hw)->setup_queue(hw, vq) < 0) {
 		PMD_INIT_LOG(ERR, "setup_queue failed");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto clean_vq;
 	}
 
 	return 0;
 
-fail_q_alloc:
+clean_vq:
+	hw->cvq = NULL;
 	rte_free(sw_ring);
+free_hdr_mz:
 	rte_memzone_free(hdr_mz);
+free_mz:
 	rte_memzone_free(mz);
+free_vq:
 	rte_free(vq);
 
 	return ret;
-- 
2.29.2

[dpdk-dev] [PATCH v4 3/4] net/virtio: allocate fake mbuf in Rx queue

[Maxime Coquelin]

While it is worth clarifying whether the fake mbuf
in virtnet_rx struct is really necessary, it is sure
that it heavily impacts cache usage by being part of
the struct. Indeed, it uses two cachelines, and
requires alignment on a cacheline.

Before this series, it means it took 120 bytes in
virtnet_rx struct:

struct virtnet_rx {
	struct virtqueue *         vq;                   /*     0     8 */

	/* XXX 56 bytes hole, try to pack */

	/* --- cacheline 1 boundary (64 bytes) --- */
	struct rte_mbuf            fake_mbuf __attribute__((__aligned__(64))); /*    64   128 */
	/* --- cacheline 3 boundary (192 bytes) --- */

This patch allocates it using malloc in order to optimize
virtnet_rx cache usage and so virtqueue cache usage.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c | 13 +++++++++++++
 drivers/net/virtio/virtio_rxtx.c   |  9 +++------
 drivers/net/virtio/virtio_rxtx.h   |  2 +-
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index d5643733f7..be9faa3b6c 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -435,6 +435,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 	int queue_type = virtio_get_queue_type(hw, queue_idx);
 	int ret;
 	int numa_node = dev->device->numa_node;
+	struct rte_mbuf *fake_mbuf = NULL;
 
 	PMD_INIT_LOG(INFO, "setting up queue: %u on NUMA node %d",
 			queue_idx, numa_node);
@@ -550,10 +551,19 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 			goto free_hdr_mz;
 		}
 
+		fake_mbuf = rte_zmalloc_socket("sw_ring", sizeof(*fake_mbuf),
+				RTE_CACHE_LINE_SIZE, numa_node);
+		if (!fake_mbuf) {
+			PMD_INIT_LOG(ERR, "can not allocate fake mbuf");
+			ret = -ENOMEM;
+			goto free_sw_ring;
+		}
+
 		vq->sw_ring = sw_ring;
 		rxvq = &vq->rxq;
 		rxvq->port_id = dev->data->port_id;
 		rxvq->mz = mz;
+		rxvq->fake_mbuf = fake_mbuf;
 	} else if (queue_type == VTNET_TQ) {
 		txvq = &vq->txq;
 		txvq->port_id = dev->data->port_id;
@@ -612,6 +622,8 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t queue_idx)
 
 clean_vq:
 	hw->cvq = NULL;
+	rte_free(fake_mbuf);
+free_sw_ring:
 	rte_free(sw_ring);
 free_hdr_mz:
 	rte_memzone_free(hdr_mz);
@@ -641,6 +653,7 @@ virtio_free_queues(struct virtio_hw *hw)
 
 		queue_type = virtio_get_queue_type(hw, i);
 		if (queue_type == VTNET_RQ) {
+			rte_free(vq->rxq.fake_mbuf);
 			rte_free(vq->sw_ring);
 			rte_memzone_free(vq->rxq.mz);
 		} else if (queue_type == VTNET_TQ) {
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 32af8d3d11..8df913b0ba 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -703,12 +703,9 @@ virtio_dev_rx_queue_setup_finish(struct rte_eth_dev *dev, uint16_t queue_idx)
 		virtio_rxq_vec_setup(rxvq);
 	}
 
-	memset(&rxvq->fake_mbuf, 0, sizeof(rxvq->fake_mbuf));
-	for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST;
-	     desc_idx++) {
-		vq->sw_ring[vq->vq_nentries + desc_idx] =
-			&rxvq->fake_mbuf;
-	}
+	memset(rxvq->fake_mbuf, 0, sizeof(*rxvq->fake_mbuf));
+	for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST; desc_idx++)
+		vq->sw_ring[vq->vq_nentries + desc_idx] = rxvq->fake_mbuf;
 
 	if (hw->use_vec_rx && !virtio_with_packed_queue(hw)) {
 		while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
diff --git a/drivers/net/virtio/virtio_rxtx.h b/drivers/net/virtio/virtio_rxtx.h
index 7f1036be6f..6ce5d67d15 100644
--- a/drivers/net/virtio/virtio_rxtx.h
+++ b/drivers/net/virtio/virtio_rxtx.h
@@ -19,7 +19,7 @@ struct virtnet_stats {
 
 struct virtnet_rx {
 	/* dummy mbuf, for wraparound when processing RX ring. */
-	struct rte_mbuf fake_mbuf;
+	struct rte_mbuf *fake_mbuf;
 	uint64_t mbuf_initializer; /**< value to init mbufs. */
 	struct rte_mempool *mpool; /**< mempool for mbuf allocation */
 
-- 
2.29.2

[dpdk-dev] [PATCH v4 4/4] net/virtio: pack virtqueue struct

[Maxime Coquelin]

This patch optimizes packing of the virtqueue
struct by moving fields around to fill holes.

Offset field is not used and so can be removed.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
---
 drivers/net/virtio/virtqueue.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 17e76f0e8c..e9992b745d 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -244,6 +244,15 @@ struct virtqueue {
 	uint16_t vq_avail_idx; /**< sync until needed */
 	uint16_t vq_free_thresh; /**< free threshold */
 
+	/**
+	 * Head of the free chain in the descriptor table. If
+	 * there are no free descriptors, this will be set to
+	 * VQ_RING_DESC_CHAIN_END.
+	 */
+	uint16_t  vq_desc_head_idx;
+	uint16_t  vq_desc_tail_idx;
+	uint16_t  vq_queue_index;   /**< PCI queue index */
+
 	void *vq_ring_virt_mem;  /**< linear address of vring*/
 	unsigned int vq_ring_size;
 
@@ -256,15 +265,6 @@ struct virtqueue {
 	rte_iova_t vq_ring_mem; /**< physical address of vring,
 	                         * or virtual address for virtio_user. */
 
-	/**
-	 * Head of the free chain in the descriptor table. If
-	 * there are no free descriptors, this will be set to
-	 * VQ_RING_DESC_CHAIN_END.
-	 */
-	uint16_t  vq_desc_head_idx;
-	uint16_t  vq_desc_tail_idx;
-	uint16_t  vq_queue_index;
-	uint16_t offset; /**< relative offset to obtain addr in mbuf */
 	uint16_t  *notify_addr;
 	struct rte_mbuf **sw_ring;  /**< RX software ring. */
 	struct vq_desc_extra vq_descx[0];
-- 
2.29.2

Re: [dpdk-dev] [PATCH v4 2/4] net/virtio: improve queue init error path

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, March 16, 2021 5:38 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; amorenoz@redhat.com;
> david.marchand@redhat.com; olivier.matz@6wind.com; bnemeth@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v4 2/4] net/virtio: improve queue init error path
> 
> This patch improves the error path of virtio_init_queue(),
> by cleaning in reversing order all resources that have
> been allocated.
> 
> Suggested-by: Chenbo Xia <chenbo.xia@intel.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> Reviewed-by: David Marchand <david.marchand@redhat.com>
> ---
>  drivers/net/virtio/virtio_ethdev.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> index af090fdf9c..d5643733f7 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -507,7 +507,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
>  			mz = rte_memzone_lookup(vq_name);
>  		if (mz == NULL) {
>  			ret = -ENOMEM;
> -			goto fail_q_alloc;
> +			goto free_vq;
>  		}
>  	}
> 
> @@ -533,7 +533,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
>  				hdr_mz = rte_memzone_lookup(vq_hdr_name);
>  			if (hdr_mz == NULL) {
>  				ret = -ENOMEM;
> -				goto fail_q_alloc;
> +				goto free_mz;
>  			}
>  		}
>  	}
> @@ -547,7 +547,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
>  		if (!sw_ring) {
>  			PMD_INIT_LOG(ERR, "can not allocate RX soft ring");
>  			ret = -ENOMEM;
> -			goto fail_q_alloc;
> +			goto free_hdr_mz;
>  		}
> 
>  		vq->sw_ring = sw_ring;
> @@ -604,15 +604,20 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
> 
>  	if (VIRTIO_OPS(hw)->setup_queue(hw, vq) < 0) {
>  		PMD_INIT_LOG(ERR, "setup_queue failed");
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto clean_vq;
>  	}
> 
>  	return 0;
> 
> -fail_q_alloc:
> +clean_vq:
> +	hw->cvq = NULL;
>  	rte_free(sw_ring);
> +free_hdr_mz:
>  	rte_memzone_free(hdr_mz);
> +free_mz:
>  	rte_memzone_free(mz);
> +free_vq:
>  	rte_free(vq);
> 
>  	return ret;
> --
> 2.29.2

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>

Re: [dpdk-dev] [PATCH v4 3/4] net/virtio: allocate fake mbuf in Rx queue

[Xia, Chenbo]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, March 16, 2021 5:38 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; amorenoz@redhat.com;
> david.marchand@redhat.com; olivier.matz@6wind.com; bnemeth@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v4 3/4] net/virtio: allocate fake mbuf in Rx queue
> 
> While it is worth clarifying whether the fake mbuf
> in virtnet_rx struct is really necessary, it is sure
> that it heavily impacts cache usage by being part of
> the struct. Indeed, it uses two cachelines, and
> requires alignment on a cacheline.
> 
> Before this series, it means it took 120 bytes in
> virtnet_rx struct:
> 
> struct virtnet_rx {
> 	struct virtqueue *         vq;                   /*     0     8 */
> 
> 	/* XXX 56 bytes hole, try to pack */
> 
> 	/* --- cacheline 1 boundary (64 bytes) --- */
> 	struct rte_mbuf            fake_mbuf __attribute__((__aligned__(64)));
> /*    64   128 */
> 	/* --- cacheline 3 boundary (192 bytes) --- */
> 
> This patch allocates it using malloc in order to optimize
> virtnet_rx cache usage and so virtqueue cache usage.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> Reviewed-by: David Marchand <david.marchand@redhat.com>
> ---
>  drivers/net/virtio/virtio_ethdev.c | 13 +++++++++++++
>  drivers/net/virtio/virtio_rxtx.c   |  9 +++------
>  drivers/net/virtio/virtio_rxtx.h   |  2 +-
>  3 files changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> index d5643733f7..be9faa3b6c 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -435,6 +435,7 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
>  	int queue_type = virtio_get_queue_type(hw, queue_idx);
>  	int ret;
>  	int numa_node = dev->device->numa_node;
> +	struct rte_mbuf *fake_mbuf = NULL;
> 
>  	PMD_INIT_LOG(INFO, "setting up queue: %u on NUMA node %d",
>  			queue_idx, numa_node);
> @@ -550,10 +551,19 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
>  			goto free_hdr_mz;
>  		}
> 
> +		fake_mbuf = rte_zmalloc_socket("sw_ring", sizeof(*fake_mbuf),
> +				RTE_CACHE_LINE_SIZE, numa_node);
> +		if (!fake_mbuf) {
> +			PMD_INIT_LOG(ERR, "can not allocate fake mbuf");
> +			ret = -ENOMEM;
> +			goto free_sw_ring;
> +		}
> +
>  		vq->sw_ring = sw_ring;
>  		rxvq = &vq->rxq;
>  		rxvq->port_id = dev->data->port_id;
>  		rxvq->mz = mz;
> +		rxvq->fake_mbuf = fake_mbuf;
>  	} else if (queue_type == VTNET_TQ) {
>  		txvq = &vq->txq;
>  		txvq->port_id = dev->data->port_id;
> @@ -612,6 +622,8 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t
> queue_idx)
> 
>  clean_vq:
>  	hw->cvq = NULL;
> +	rte_free(fake_mbuf);
> +free_sw_ring:
>  	rte_free(sw_ring);
>  free_hdr_mz:
>  	rte_memzone_free(hdr_mz);
> @@ -641,6 +653,7 @@ virtio_free_queues(struct virtio_hw *hw)
> 
>  		queue_type = virtio_get_queue_type(hw, i);
>  		if (queue_type == VTNET_RQ) {
> +			rte_free(vq->rxq.fake_mbuf);
>  			rte_free(vq->sw_ring);
>  			rte_memzone_free(vq->rxq.mz);
>  		} else if (queue_type == VTNET_TQ) {
> diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> index 32af8d3d11..8df913b0ba 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -703,12 +703,9 @@ virtio_dev_rx_queue_setup_finish(struct rte_eth_dev *dev,
> uint16_t queue_idx)
>  		virtio_rxq_vec_setup(rxvq);
>  	}
> 
> -	memset(&rxvq->fake_mbuf, 0, sizeof(rxvq->fake_mbuf));
> -	for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST;
> -	     desc_idx++) {
> -		vq->sw_ring[vq->vq_nentries + desc_idx] =
> -			&rxvq->fake_mbuf;
> -	}
> +	memset(rxvq->fake_mbuf, 0, sizeof(*rxvq->fake_mbuf));
> +	for (desc_idx = 0; desc_idx < RTE_PMD_VIRTIO_RX_MAX_BURST; desc_idx++)

I just notice that the macro 'RTE_PMD_VIRTIO_RX_MAX_BURST' and 'RTE_VIRTIO_VPMD_RX_BURST'
should always have the same value, so maybe better to make them into one macro later?

For this patch:

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>

> +		vq->sw_ring[vq->vq_nentries + desc_idx] = rxvq->fake_mbuf;
> 
>  	if (hw->use_vec_rx && !virtio_with_packed_queue(hw)) {
>  		while (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
> diff --git a/drivers/net/virtio/virtio_rxtx.h
> b/drivers/net/virtio/virtio_rxtx.h
> index 7f1036be6f..6ce5d67d15 100644
> --- a/drivers/net/virtio/virtio_rxtx.h
> +++ b/drivers/net/virtio/virtio_rxtx.h
> @@ -19,7 +19,7 @@ struct virtnet_stats {
> 
>  struct virtnet_rx {
>  	/* dummy mbuf, for wraparound when processing RX ring. */
> -	struct rte_mbuf fake_mbuf;
> +	struct rte_mbuf *fake_mbuf;
>  	uint64_t mbuf_initializer; /**< value to init mbufs. */
>  	struct rte_mempool *mpool; /**< mempool for mbuf allocation */
> 
> --
> 2.29.2

Re: [dpdk-dev] [PATCH v4 0/4] net/virtio: make virtqueue struct cache-friendly

[Balazs Nemeth]

On Tue, 2021-03-16 at 10:38 +0100, Maxime Coquelin wrote:
> This series optimizes the cache usage of virtqueue struct,
> by making a "fake" mbuf being dynamically allocated in Rx
> virtnet struct, by removing a useless virtuque pointer
> into the virtnet structs and by moving a few fields
> to pack holes.
> 
> With these 3 patches, the virtqueue struct size goes from
> 576 bytes (9 cachelines) to 248 bytes (4 cachelines).
> 
> Changes in v4:
> ==============
> - Fix ARM build failure after rebase (0-day robot)
> - Fix fake_mbuf freeing (David)
> - Applied David R-by
> 
> Changes in v3:
> ==============
> - Use rte_zmalloc_socket for fake mbuf alloc (David)
> - Fix typos in commit messages
> - Remove superfluous pointer check befor freeing (David)
> - Fix checkpatch warnings
> 
> Changes in v2:
> ==============
> - Rebase on latest main
> - Improve error path in virtio_init_queue
> - Fix various typos in commit messages
> 
> Maxime Coquelin (4):
>   net/virtio: remove reference to virtqueue in vrings
>   net/virtio: improve queue init error path
>   net/virtio: allocate fake mbuf in Rx queue
>   net/virtio: pack virtqueue struct
> 
>  drivers/net/virtio/virtio_ethdev.c            | 64 +++++++++++--------
>  drivers/net/virtio/virtio_rxtx.c              | 37 +++++------
>  drivers/net/virtio/virtio_rxtx.h              |  5 +-
>  drivers/net/virtio/virtio_rxtx_packed.c       |  4 +-
>  drivers/net/virtio/virtio_rxtx_packed.h       |  6 +-
>  drivers/net/virtio/virtio_rxtx_packed_avx.h   |  4 +-
>  drivers/net/virtio/virtio_rxtx_packed_neon.h  |  4 +-
>  drivers/net/virtio/virtio_rxtx_simple.h       |  2 +-
>  .../net/virtio/virtio_rxtx_simple_altivec.c   |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple_neon.c  |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple_sse.c   |  2 +-
>  .../net/virtio/virtio_user/virtio_user_dev.c  |  4 +-
>  drivers/net/virtio/virtio_user_ethdev.c       |  2 +-
>  drivers/net/virtio/virtqueue.h                | 24 ++++---
>  14 files changed, 87 insertions(+), 75 deletions(-)
> 


Tested this in a PVP setup on ARM, giving a slight improvement in
performance. For the series:

Tested-by: Balazs Nemeth <bnemeth@redhat.com>

Re: [dpdk-dev] [PATCH v4 0/4] net/virtio: make virtqueue struct cache-friendly

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, March 16, 2021 5:38 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; amorenoz@redhat.com;
> david.marchand@redhat.com; olivier.matz@6wind.com; bnemeth@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v4 0/4] net/virtio: make virtqueue struct cache-friendly
> 
> This series optimizes the cache usage of virtqueue struct,
> by making a "fake" mbuf being dynamically allocated in Rx
> virtnet struct, by removing a useless virtuque pointer
> into the virtnet structs and by moving a few fields
> to pack holes.
> 
>  drivers/net/virtio/virtio_ethdev.c            | 64 +++++++++++--------
>  drivers/net/virtio/virtio_rxtx.c              | 37 +++++------
>  drivers/net/virtio/virtio_rxtx.h              |  5 +-
>  drivers/net/virtio/virtio_rxtx_packed.c       |  4 +-
>  drivers/net/virtio/virtio_rxtx_packed.h       |  6 +-
>  drivers/net/virtio/virtio_rxtx_packed_avx.h   |  4 +-
>  drivers/net/virtio/virtio_rxtx_packed_neon.h  |  4 +-
>  drivers/net/virtio/virtio_rxtx_simple.h       |  2 +-
>  .../net/virtio/virtio_rxtx_simple_altivec.c   |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple_neon.c  |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple_sse.c   |  2 +-
>  .../net/virtio/virtio_user/virtio_user_dev.c  |  4 +-
>  drivers/net/virtio/virtio_user_ethdev.c       |  2 +-
>  drivers/net/virtio/virtqueue.h                | 24 ++++---
>  14 files changed, 87 insertions(+), 75 deletions(-)
> 
> --
> 2.29.2

With below commit log change(because of commit log line too long)

    net/virtio: allocate fake mbuf in Rx queue
    [...]
    struct virtnet_rx {
     struct virtqueue *vq; /*0 8*/

     /* XXX 56 bytes hole, try to pack */

     /* --- cacheline 1 boundary (64 bytes) --- */
     struct rte_mbuf fake_mbuf __attribute__((__aligned__(64))); /*64 128*/
     /* --- cacheline 3 boundary (192 bytes) --- */

Series applied to next-virtio/main.

Thanks!
Chenbo