Re: [PATCH v5 07/11] net/virtio: implement transmit path for packed queues
From: Tiwei Bie <hidden>
Date: 2018-09-13 09:18:04
On Thu, Sep 06, 2018 at 07:19:43PM +0100, Jens Freimann wrote:
This implements the transmit path for devices with support for packed virtqueues. Add the feature bit and enable code to add buffers to vring and mark descriptors as available. Signed-off-by: Jens Freiman <redacted> --- drivers/net/virtio/virtio_ethdev.c | 8 +- drivers/net/virtio/virtio_ethdev.h | 2 + drivers/net/virtio/virtio_rxtx.c | 113 ++++++++++++++++++++++++++++- 3 files changed, 121 insertions(+), 2 deletions(-)
[...]
+
+uint16_t
+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;
+ uint16_t i;
+ struct vring_desc_packed *desc = vq->vq_ring.desc_packed;
+ uint16_t idx, prev;
+ struct vq_desc_extra *dxp;
+
+ if (unlikely(nb_pkts < 1))
+ return nb_pkts;
+
+ PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts);
+
+ if (likely(vq->vq_free_cnt < vq->vq_free_thresh))
+ virtio_xmit_cleanup_packed(vq);
+
+ for (i = 0; i < nb_pkts; i++) {
+ struct rte_mbuf *txm = tx_pkts[i];
+ struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
+ uint16_t head_idx;
+ int wrap_counter;
+ int descs_used;
+
+ if (unlikely(txm->nb_segs + 1 > vq->vq_free_cnt)) {
+ virtio_xmit_cleanup_packed(vq);
+
+ if (unlikely(txm->nb_segs + 1 > vq->vq_free_cnt)) {
+ PMD_TX_LOG(ERR,
+ "No free tx descriptors to transmit");
+ break;
+ }
+ }
+
+ txvq->stats.bytes += txm->pkt_len;
+We also need to update the stats by calling virtio_update_packet_stats() We also need to handle the offloads. See virtqueue_xmit_offload().
quoted hunk ↗ jump to hunk
+ vq->vq_free_cnt -= txm->nb_segs + 1; + + wrap_counter = vq->vq_ring.avail_wrap_counter; + idx = vq->vq_avail_idx; + head_idx = idx; + + dxp = &vq->vq_descx[idx]; + if (dxp->cookie != NULL) + rte_pktmbuf_free(dxp->cookie); + dxp->cookie = txm; + + desc[idx].addr = txvq->virtio_net_hdr_mem + + RTE_PTR_DIFF(&txr[idx].tx_hdr, txr); + desc[idx].len = vq->hw->vtnet_hdr_size; + desc[idx].flags = VRING_DESC_F_NEXT | + VRING_DESC_F_AVAIL(vq->vq_ring.avail_wrap_counter) | + VRING_DESC_F_USED(!vq->vq_ring.avail_wrap_counter); + descs_used = 1; + + do { + idx = update_pq_avail_index(vq); + desc[idx].addr = VIRTIO_MBUF_DATA_DMA_ADDR(txm, vq); + desc[idx].len = txm->data_len; + desc[idx].flags = VRING_DESC_F_NEXT | + VRING_DESC_F_AVAIL(vq->vq_ring.avail_wrap_counter) | + VRING_DESC_F_USED(!vq->vq_ring.avail_wrap_counter); + descs_used++; + } while ((txm = txm->next) != NULL); + + desc[idx].flags &= ~VRING_DESC_F_NEXT; + + rte_smp_wmb(); + prev = (idx > 0 ? idx : vq->vq_nentries) - 1; + desc[prev].index = head_idx; //FIXME + desc[head_idx].flags = + (VRING_DESC_F_AVAIL(wrap_counter) | + VRING_DESC_F_USED(!wrap_counter)); + + vq->vq_descx[head_idx].ndescs = descs_used; + idx = update_pq_avail_index(vq); + } + + txvq->stats.packets += i; + txvq->stats.errors += nb_pkts - i; + + return i; +} + int virtio_dev_rx_queue_done(void *rxq, uint16_t offset) {@@ -736,7 +842,12 @@ virtio_dev_tx_queue_setup_finish(struct rte_eth_dev *dev, if (hw->use_inorder_tx) vq->vq_ring.desc[vq->vq_nentries - 1].next = 0; - VIRTQUEUE_DUMP(vq); + if (vtpci_packed_queue(hw)) { + vq->vq_ring.avail_wrap_counter = 1; + } + + if (!vtpci_packed_queue(hw)) + VIRTQUEUE_DUMP(vq); return 0; }-- 2.17.1