virtio: add simple Tx

Bulk free of mbufs when clean used ring.
Shift operation of idx could be saved if vq_free_cnt means
free slots rather than free descriptors.

TODO: rearrange vq data structure, pack the stats var together so that
we could use one vec instruction to update all of them.

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
Acked-by: Jianfeng Tan <jianfeng.tan@intel.com>

diff --git a/doc/guides/rel_notes/release_2_2.rst b/doc/guides/rel_notes/release_2_2.rst
index c523e57..16209d2 100644 (file)
--- a/doc/guides/rel_notes/release_2_2.rst
+++ b/doc/guides/rel_notes/release_2_2.rst
@@ -59,6 +59,7 @@ New Features
 
   * Virtio ring layout optimization (fixed avail ring)
   * Vector RX
+  * Simple TX
 
 * **Added vhost-user multiple queue support.**
 

diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
index d7797ab..ae2d47d 100644 (file)
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -111,6 +111,9 @@ uint16_t virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 uint16_t virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
                uint16_t nb_pkts);
 
+uint16_t virtio_xmit_pkts_simple(void *tx_queue, struct rte_mbuf **tx_pkts,
+               uint16_t nb_pkts);
+
 /*
  * The VIRTIO_NET_F_GUEST_TSO[46] features permit the host to send us
  * frames larger than 1514 bytes. We do not yet support software LRO

diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c
index f6c00c1..ff3c11a 100644 (file)
--- a/drivers/net/virtio/virtio_rxtx_simple.c
+++ b/drivers/net/virtio/virtio_rxtx_simple.c
@@ -292,6 +292,112 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
        return nb_pkts_received;
 }
 
+#define VIRTIO_TX_FREE_THRESH 32
+#define VIRTIO_TX_MAX_FREE_BUF_SZ 32
+#define VIRTIO_TX_FREE_NR 32
+/* TODO: vq->tx_free_cnt could mean num of free slots so we could avoid shift */
+static inline void
+virtio_xmit_cleanup(struct virtqueue *vq)
+{
+       uint16_t i, desc_idx;
+       int nb_free = 0;
+       struct rte_mbuf *m, *free[VIRTIO_TX_MAX_FREE_BUF_SZ];
+
+       desc_idx = (uint16_t)(vq->vq_used_cons_idx &
+                  ((vq->vq_nentries >> 1) - 1));
+       m = (struct rte_mbuf *)vq->vq_descx[desc_idx++].cookie;
+       m = __rte_pktmbuf_prefree_seg(m);
+       if (likely(m != NULL)) {
+               free[0] = m;
+               nb_free = 1;
+               for (i = 1; i < VIRTIO_TX_FREE_NR; i++) {
+                       m = (struct rte_mbuf *)vq->vq_descx[desc_idx++].cookie;
+                       m = __rte_pktmbuf_prefree_seg(m);
+                       if (likely(m != NULL)) {
+                               if (likely(m->pool == free[0]->pool))
+                                       free[nb_free++] = m;
+                               else {
+                                       rte_mempool_put_bulk(free[0]->pool,
+                                               (void **)free, nb_free);
+                                       free[0] = m;
+                                       nb_free = 1;
+                               }
+                       }
+               }
+               rte_mempool_put_bulk(free[0]->pool, (void **)free, nb_free);
+       } else {
+               for (i = 1; i < VIRTIO_TX_FREE_NR; i++) {
+                       m = (struct rte_mbuf *)vq->vq_descx[desc_idx++].cookie;
+                       m = __rte_pktmbuf_prefree_seg(m);
+                       if (m != NULL)
+                               rte_mempool_put(m->pool, m);
+               }
+       }
+
+       vq->vq_used_cons_idx += VIRTIO_TX_FREE_NR;
+       vq->vq_free_cnt += (VIRTIO_TX_FREE_NR << 1);
+}
+
+uint16_t
+virtio_xmit_pkts_simple(void *tx_queue, struct rte_mbuf **tx_pkts,
+       uint16_t nb_pkts)
+{
+       struct virtqueue *txvq = tx_queue;
+       uint16_t nb_used;
+       uint16_t desc_idx;
+       struct vring_desc *start_dp;
+       uint16_t nb_tail, nb_commit;
+       int i;
+       uint16_t desc_idx_max = (txvq->vq_nentries >> 1) - 1;
+
+       nb_used = VIRTQUEUE_NUSED(txvq);
+       rte_compiler_barrier();
+
+       if (nb_used >= VIRTIO_TX_FREE_THRESH)
+               virtio_xmit_cleanup(tx_queue);
+
+       nb_commit = nb_pkts = RTE_MIN((txvq->vq_free_cnt >> 1), nb_pkts);
+       desc_idx = (uint16_t) (txvq->vq_avail_idx & desc_idx_max);
+       start_dp = txvq->vq_ring.desc;
+       nb_tail = (uint16_t) (desc_idx_max + 1 - desc_idx);
+
+       if (nb_commit >= nb_tail) {
+               for (i = 0; i < nb_tail; i++)
+                       txvq->vq_descx[desc_idx + i].cookie = tx_pkts[i];
+               for (i = 0; i < nb_tail; i++) {
+                       start_dp[desc_idx].addr =
+                               RTE_MBUF_DATA_DMA_ADDR(*tx_pkts);
+                       start_dp[desc_idx].len = (*tx_pkts)->pkt_len;
+                       tx_pkts++;
+                       desc_idx++;
+               }
+               nb_commit -= nb_tail;
+               desc_idx = 0;
+       }
+       for (i = 0; i < nb_commit; i++)
+               txvq->vq_descx[desc_idx + i].cookie = tx_pkts[i];
+       for (i = 0; i < nb_commit; i++) {
+               start_dp[desc_idx].addr = RTE_MBUF_DATA_DMA_ADDR(*tx_pkts);
+               start_dp[desc_idx].len = (*tx_pkts)->pkt_len;
+               tx_pkts++;
+               desc_idx++;
+       }
+
+       rte_compiler_barrier();
+
+       txvq->vq_free_cnt -= (uint16_t)(nb_pkts << 1);
+       txvq->vq_avail_idx += nb_pkts;
+       txvq->vq_ring.avail->idx = txvq->vq_avail_idx;
+       txvq->packets += nb_pkts;
+
+       if (likely(nb_pkts)) {
+               if (unlikely(virtqueue_kick_prepare(txvq)))
+                       virtqueue_notify(txvq);
+       }
+
+       return nb_pkts;
+}
+
 int __attribute__((cold))
 virtio_rxq_vec_setup(struct virtqueue *rxq)
 {