[dpdk-dev] [PATCH v2 5/7] virtio: virtio vec rx

[Huawei Xie <huawei.xie@intel.com>]

With fixed avail ring, we don't need to get desc idx from avail ring.
virtio driver only has to deal with desc ring.
This patch uses vector instruction to accelerate processing desc ring.

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
---
 drivers/net/virtio/virtio_ethdev.h      |   2 +
 drivers/net/virtio/virtio_rxtx.c        |   3 +
 drivers/net/virtio/virtio_rxtx.h        |   2 +
 drivers/net/virtio/virtio_rxtx_simple.c | 224 ++++++++++++++++++++++++++++++++
 drivers/net/virtio/virtqueue.h          |   1 +
 5 files changed, 232 insertions(+)

diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
index 9026d42..d7797ab 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -108,6 +108,8 @@ uint16_t virtio_recv_mergeable_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
 uint16_t virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 		uint16_t nb_pkts);
 
+uint16_t virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
+		uint16_t nb_pkts);
 
 /*
  * The VIRTIO_NET_F_GUEST_TSO[46] features permit the host to send us
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 5162ce6..947fc46 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -432,6 +432,9 @@ virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
 	vq->mpool = mp;
 
 	dev->data->rx_queues[queue_idx] = vq;
+
+	virtio_rxq_vec_setup(vq);
+
 	return 0;
 }
 
diff --git a/drivers/net/virtio/virtio_rxtx.h b/drivers/net/virtio/virtio_rxtx.h
index 7d2d8fe..831e492 100644
--- a/drivers/net/virtio/virtio_rxtx.h
+++ b/drivers/net/virtio/virtio_rxtx.h
@@ -33,5 +33,7 @@
 
 #define RTE_PMD_VIRTIO_RX_MAX_BURST 64
 
+int virtio_rxq_vec_setup(struct virtqueue *rxq);
+
 int virtqueue_enqueue_recv_refill_simple(struct virtqueue *vq,
 	struct rte_mbuf *m);
diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c
index cac5b9f..ef17562 100644
--- a/drivers/net/virtio/virtio_rxtx_simple.c
+++ b/drivers/net/virtio/virtio_rxtx_simple.c
@@ -58,6 +58,10 @@
 #include "virtqueue.h"
 #include "virtio_rxtx.h"
 
+#define RTE_VIRTIO_VPMD_RX_BURST 32
+#define RTE_VIRTIO_DESC_PER_LOOP 8
+#define RTE_VIRTIO_VPMD_RX_REARM_THRESH RTE_VIRTIO_VPMD_RX_BURST
+
 int __attribute__((cold))
 virtqueue_enqueue_recv_refill_simple(struct virtqueue *vq,
 	struct rte_mbuf *cookie)
@@ -82,3 +86,223 @@ virtqueue_enqueue_recv_refill_simple(struct virtqueue *vq,
 
 	return 0;
 }
+
+static inline void
+virtio_rxq_rearm_vec(struct virtqueue *rxvq)
+{
+	int i;
+	uint16_t desc_idx;
+	struct rte_mbuf **sw_ring;
+	struct vring_desc *start_dp;
+	int ret;
+
+	desc_idx = rxvq->vq_avail_idx & (rxvq->vq_nentries - 1);
+	sw_ring = &rxvq->sw_ring[desc_idx];
+	start_dp = &rxvq->vq_ring.desc[desc_idx];
+
+	ret = rte_mempool_get_bulk(rxvq->mpool, (void **)sw_ring,
+		RTE_VIRTIO_VPMD_RX_REARM_THRESH);
+	if (unlikely(ret)) {
+		rte_eth_devices[rxvq->port_id].data->rx_mbuf_alloc_failed +=
+			RTE_VIRTIO_VPMD_RX_REARM_THRESH;
+		return;
+	}
+
+	for (i = 0; i < RTE_VIRTIO_VPMD_RX_REARM_THRESH; i++) {
+		uintptr_t p;
+
+		p = (uintptr_t)&sw_ring[i]->rearm_data;
+		*(uint64_t *)p = rxvq->mbuf_initializer;
+
+		start_dp[i].addr =
+			(uint64_t)((uintptr_t)sw_ring[i]->buf_physaddr +
+			RTE_PKTMBUF_HEADROOM - sizeof(struct virtio_net_hdr));
+		start_dp[i].len = sw_ring[i]->buf_len -
+			RTE_PKTMBUF_HEADROOM + sizeof(struct virtio_net_hdr);
+	}
+
+	rxvq->vq_avail_idx += RTE_VIRTIO_VPMD_RX_REARM_THRESH;
+	rxvq->vq_free_cnt -= RTE_VIRTIO_VPMD_RX_REARM_THRESH;
+	vq_update_avail_idx(rxvq);
+}
+
+/* virtio vPMD receive routine, only accept(nb_pkts >= RTE_VIRTIO_DESC_PER_LOOP)
+ *
+ * This routine is for non-mergable RX, one desc for each guest buffer.
+ * This routine is based on the RX ring layout optimization. Each entry in the
+ * avail ring points to the desc with the same index in the desc ring and this
+ * will never be changed in the driver.
+ *
+ * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
+ */
+uint16_t
+virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
+	uint16_t nb_pkts)
+{
+	struct virtqueue *rxvq = rx_queue;
+	uint16_t nb_used;
+	uint16_t desc_idx;
+	struct vring_used_elem *rused;
+	struct rte_mbuf **sw_ring;
+	struct rte_mbuf **sw_ring_end;
+	uint16_t nb_pkts_received;
+	__m128i shuf_msk1, shuf_msk2, len_adjust;
+
+	shuf_msk1 = _mm_set_epi8(
+		0xFF, 0xFF, 0xFF, 0xFF,
+		0xFF, 0xFF,		/* vlan tci */
+		5, 4,			/* dat len */
+		0xFF, 0xFF, 5, 4,	/* pkt len */
+		0xFF, 0xFF, 0xFF, 0xFF	/* packet type */
+
+	);
+
+	shuf_msk2 = _mm_set_epi8(
+		0xFF, 0xFF, 0xFF, 0xFF,
+		0xFF, 0xFF,		/* vlan tci */
+		13, 12,			/* dat len */
+		0xFF, 0xFF, 13, 12,	/* pkt len */
+		0xFF, 0xFF, 0xFF, 0xFF	/* packet type */
+	);
+
+	/* Substract the header length.
+	*  In which case do we need the header length in used->len ?
+	*/
+	len_adjust = _mm_set_epi16(
+		0, 0,
+		0,
+		(uint16_t) -sizeof(struct virtio_net_hdr),
+		0, (uint16_t) -sizeof(struct virtio_net_hdr),
+		0, 0);
+
+	if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP))
+		return 0;
+
+	nb_used = *(volatile uint16_t *)&rxvq->vq_ring.used->idx -
+		rxvq->vq_used_cons_idx;
+
+	rte_compiler_barrier();
+
+	if (unlikely(nb_used == 0))
+		return 0;
+
+	nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_VIRTIO_DESC_PER_LOOP);
+	nb_used = RTE_MIN(nb_used, nb_pkts);
+
+	desc_idx = (uint16_t)(rxvq->vq_used_cons_idx & (rxvq->vq_nentries - 1));
+	rused = &rxvq->vq_ring.used->ring[desc_idx];
+	sw_ring  = &rxvq->sw_ring[desc_idx];
+	sw_ring_end = &rxvq->sw_ring[rxvq->vq_nentries];
+
+	_mm_prefetch((const void *)rused, _MM_HINT_T0);
+
+	if (rxvq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) {
+		virtio_rxq_rearm_vec(rxvq);
+		if (unlikely(virtqueue_kick_prepare(rxvq)))
+			virtqueue_notify(rxvq);
+	}
+
+	for (nb_pkts_received = 0;
+		nb_pkts_received < nb_used;) {
+		__m128i desc[RTE_VIRTIO_DESC_PER_LOOP / 2];
+		__m128i mbp[RTE_VIRTIO_DESC_PER_LOOP / 2];
+		__m128i pkt_mb[RTE_VIRTIO_DESC_PER_LOOP];
+
+		mbp[0] = _mm_loadu_si128((__m128i *)(sw_ring + 0));
+		desc[0] = _mm_loadu_si128((__m128i *)(rused + 0));
+		_mm_storeu_si128((__m128i *)&rx_pkts[0], mbp[0]);
+
+		mbp[1] = _mm_loadu_si128((__m128i *)(sw_ring + 2));
+		desc[1] = _mm_loadu_si128((__m128i *)(rused + 2));
+		_mm_storeu_si128((__m128i *)&rx_pkts[2], mbp[1]);
+
+		mbp[2] = _mm_loadu_si128((__m128i *)(sw_ring + 4));
+		desc[2] = _mm_loadu_si128((__m128i *)(rused + 4));
+		_mm_storeu_si128((__m128i *)&rx_pkts[4], mbp[2]);
+
+		mbp[3] = _mm_loadu_si128((__m128i *)(sw_ring + 6));
+		desc[3] = _mm_loadu_si128((__m128i *)(rused + 6));
+		_mm_storeu_si128((__m128i *)&rx_pkts[6], mbp[3]);
+
+		pkt_mb[1] = _mm_shuffle_epi8(desc[0], shuf_msk2);
+		pkt_mb[0] = _mm_shuffle_epi8(desc[0], shuf_msk1);
+		pkt_mb[1] = _mm_add_epi16(pkt_mb[1], len_adjust);
+		pkt_mb[0] = _mm_add_epi16(pkt_mb[0], len_adjust);
+		_mm_storeu_si128((void *)&rx_pkts[1]->rx_descriptor_fields1,
+			pkt_mb[1]);
+		_mm_storeu_si128((void *)&rx_pkts[0]->rx_descriptor_fields1,
+			pkt_mb[0]);
+
+		pkt_mb[3] = _mm_shuffle_epi8(desc[1], shuf_msk2);
+		pkt_mb[2] = _mm_shuffle_epi8(desc[1], shuf_msk1);
+		pkt_mb[3] = _mm_add_epi16(pkt_mb[3], len_adjust);
+		pkt_mb[2] = _mm_add_epi16(pkt_mb[2], len_adjust);
+		_mm_storeu_si128((void *)&rx_pkts[3]->rx_descriptor_fields1,
+			pkt_mb[3]);
+		_mm_storeu_si128((void *)&rx_pkts[2]->rx_descriptor_fields1,
+			pkt_mb[2]);
+
+		pkt_mb[5] = _mm_shuffle_epi8(desc[2], shuf_msk2);
+		pkt_mb[4] = _mm_shuffle_epi8(desc[2], shuf_msk1);
+		pkt_mb[5] = _mm_add_epi16(pkt_mb[5], len_adjust);
+		pkt_mb[4] = _mm_add_epi16(pkt_mb[4], len_adjust);
+		_mm_storeu_si128((void *)&rx_pkts[5]->rx_descriptor_fields1,
+			pkt_mb[5]);
+		_mm_storeu_si128((void *)&rx_pkts[4]->rx_descriptor_fields1,
+			pkt_mb[4]);
+
+		pkt_mb[7] = _mm_shuffle_epi8(desc[3], shuf_msk2);
+		pkt_mb[6] = _mm_shuffle_epi8(desc[3], shuf_msk1);
+		pkt_mb[7] = _mm_add_epi16(pkt_mb[7], len_adjust);
+		pkt_mb[6] = _mm_add_epi16(pkt_mb[6], len_adjust);
+		_mm_storeu_si128((void *)&rx_pkts[7]->rx_descriptor_fields1,
+			pkt_mb[7]);
+		_mm_storeu_si128((void *)&rx_pkts[6]->rx_descriptor_fields1,
+			pkt_mb[6]);
+
+		if (unlikely(nb_used <= RTE_VIRTIO_DESC_PER_LOOP)) {
+			if (sw_ring + nb_used <= sw_ring_end)
+				nb_pkts_received += nb_used;
+			else
+				nb_pkts_received += sw_ring_end - sw_ring;
+			break;
+		} else {
+			if (unlikely(sw_ring + RTE_VIRTIO_DESC_PER_LOOP >=
+				sw_ring_end)) {
+				nb_pkts_received += sw_ring_end - sw_ring;
+				break;
+			} else {
+				nb_pkts_received += RTE_VIRTIO_DESC_PER_LOOP;
+
+				rx_pkts += RTE_VIRTIO_DESC_PER_LOOP;
+				sw_ring += RTE_VIRTIO_DESC_PER_LOOP;
+				rused   += RTE_VIRTIO_DESC_PER_LOOP;
+				nb_used -= RTE_VIRTIO_DESC_PER_LOOP;
+			}
+		}
+	}
+
+	rxvq->vq_used_cons_idx += nb_pkts_received;
+	rxvq->vq_free_cnt += nb_pkts_received;
+	rxvq->packets += nb_pkts_received;
+	return nb_pkts_received;
+}
+
+int __attribute__((cold))
+virtio_rxq_vec_setup(struct virtqueue *rxq)
+{
+	uintptr_t p;
+	struct rte_mbuf mb_def = { .buf_addr = 0 }; /* zeroed mbuf */
+
+	mb_def.nb_segs = 1;
+	mb_def.data_off = RTE_PKTMBUF_HEADROOM;
+	mb_def.port = rxq->port_id;
+	rte_mbuf_refcnt_set(&mb_def, 1);
+
+	/* prevent compiler reordering: rearm_data covers previous fields */
+	rte_compiler_barrier();
+	p = (uintptr_t)&mb_def.rearm_data;
+	rxq->mbuf_initializer = *(uint64_t *)p;
+
+	return 0;
+}
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 6a1ec48..98a77d5 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -188,6 +188,7 @@ struct virtqueue {
 	 */
 	uint16_t vq_used_cons_idx;
 	uint16_t vq_avail_idx;
+	uint64_t mbuf_initializer; /**< value to init mbufs. */
 	phys_addr_t virtio_net_hdr_mem; /**< hdr for each xmit packet */
 
 	struct rte_mbuf **sw_ring; /**< RX software ring. */
-- 
1.8.1.4