[ovs-dev] [RFC] dpdk: support multiple queues in vhost

Thomas F Herbert thomasfherbert at gmail.com
Thu Aug 6 16:39:29 UTC 2015


On 7/31/15 6:30 PM, Flavio Leitner wrote:
> This RFC is based on the vhost multiple queues work on
> dpdk-dev: http://dpdk.org/ml/archives/dev/2015-June/019345.html
>
> Signed-off-by: Flavio Leitner <fbl at redhat.com>
> ---
>   lib/netdev-dpdk.c | 61 ++++++++++++++++++++++++++++++++++++-------------------
>   1 file changed, 40 insertions(+), 21 deletions(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index 5ae805e..493172c 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -215,12 +215,9 @@ struct netdev_dpdk {
>        * If the numbers match, 'txq_needs_locking' is false, otherwise it is
>        * true and we will take a spinlock on transmission */
>       int real_n_txq;
> +    int real_n_rxq;
>       bool txq_needs_locking;
>
> -    /* Spinlock for vhost transmission.  Other DPDK devices use spinlocks in
> -     * dpdk_tx_queue */
> -    rte_spinlock_t vhost_tx_lock;
> -
>       /* virtio-net structure for vhost device */
>       OVSRCU_TYPE(struct virtio_net *) virtio_dev;
>
> @@ -602,13 +599,10 @@ dpdk_dev_parse_name(const char dev_name[], const char prefix[],
>   static int
>   vhost_construct_helper(struct netdev *netdev_) OVS_REQUIRES(dpdk_mutex)
>   {
> -    struct netdev_dpdk *netdev = netdev_dpdk_cast(netdev_);
> -
>       if (rte_eal_init_ret) {
>           return rte_eal_init_ret;
>       }
>
> -    rte_spinlock_init(&netdev->vhost_tx_lock);
>       return netdev_dpdk_init(netdev_, -1, DPDK_DEV_VHOST);
>   }
>
> @@ -791,9 +785,16 @@ netdev_dpdk_vhost_set_multiq(struct netdev *netdev_, unsigned int n_txq,
>       ovs_mutex_lock(&dpdk_mutex);
>       ovs_mutex_lock(&netdev->mutex);
>
> +    rte_free(netdev->tx_q);
> +    /* FIXME: the number of vqueues needs to match */
>       netdev->up.n_txq = n_txq;
> -    netdev->real_n_txq = 1;
> -    netdev->up.n_rxq = 1;
> +    netdev->up.n_rxq = n_rxq;
> +
> +    /* vring has txq = rxq */
> +    netdev->real_n_txq = n_rxq;
> +    netdev->real_n_rxq = n_rxq;
> +    netdev->txq_needs_locking = netdev->real_n_txq != netdev->up.n_txq;
> +    netdev_dpdk_alloc_txq(netdev, netdev->up.n_txq);
>
>       ovs_mutex_unlock(&netdev->mutex);
>       ovs_mutex_unlock(&dpdk_mutex);
> @@ -904,14 +905,14 @@ netdev_dpdk_vhost_rxq_recv(struct netdev_rxq *rxq_,
>       struct netdev *netdev = rx->up.netdev;
>       struct netdev_dpdk *vhost_dev = netdev_dpdk_cast(netdev);
>       struct virtio_net *virtio_dev = netdev_dpdk_get_virtio(vhost_dev);
> -    int qid = 1;
> +    int qid = rxq_->queue_id;
>       uint16_t nb_rx = 0;
>
>       if (OVS_UNLIKELY(!is_vhost_running(virtio_dev))) {
>           return EAGAIN;
>       }
>
> -    nb_rx = rte_vhost_dequeue_burst(virtio_dev, qid,
> +    nb_rx = rte_vhost_dequeue_burst(virtio_dev, VIRTIO_TXQ + qid * 2,
>                                       vhost_dev->dpdk_mp->mp,
>                                       (struct rte_mbuf **)packets,
>                                       NETDEV_MAX_BURST);
> @@ -958,8 +959,9 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq_, struct dp_packet **packets,
>   }
>
>   static void
> -__netdev_dpdk_vhost_send(struct netdev *netdev, struct dp_packet **pkts,
> -                         int cnt, bool may_steal)
> +__netdev_dpdk_vhost_send(struct netdev *netdev, int qid,
> +                         struct dp_packet **pkts, int cnt,
> +                         bool may_steal)
>   {
>       struct netdev_dpdk *vhost_dev = netdev_dpdk_cast(netdev);
>       struct virtio_net *virtio_dev = netdev_dpdk_get_virtio(vhost_dev);
> @@ -974,13 +976,16 @@ __netdev_dpdk_vhost_send(struct netdev *netdev, struct dp_packet **pkts,
>           goto out;
>       }
>
> -    /* There is vHost TX single queue, So we need to lock it for TX. */
> -    rte_spinlock_lock(&vhost_dev->vhost_tx_lock);
> +    if (vhost_dev->txq_needs_locking) {
> +        qid = qid % vhost_dev->real_n_txq;
> +        rte_spinlock_lock(&vhost_dev->tx_q[qid].tx_lock);
> +    }
>
>       do {
> +        int vhost_qid = VIRTIO_RXQ + qid * VIRTIO_QNUM;
>           unsigned int tx_pkts;
>
> -        tx_pkts = rte_vhost_enqueue_burst(virtio_dev, VIRTIO_RXQ,
> +        tx_pkts = rte_vhost_enqueue_burst(virtio_dev, vhost_qid,
>                                             cur_pkts, cnt);
>           if (OVS_LIKELY(tx_pkts)) {
>               /* Packets have been sent.*/
> @@ -999,7 +1004,7 @@ __netdev_dpdk_vhost_send(struct netdev *netdev, struct dp_packet **pkts,
>                * Unable to enqueue packets to vhost interface.
>                * Check available entries before retrying.
>                */
> -            while (!rte_vring_available_entries(virtio_dev, VIRTIO_RXQ)) {
> +            while (!rte_vring_available_entries(virtio_dev, vhost_qid)) {
>                   if (OVS_UNLIKELY((rte_get_timer_cycles() - start) > timeout)) {
>                       expired = 1;
>                       break;
> @@ -1011,7 +1016,10 @@ __netdev_dpdk_vhost_send(struct netdev *netdev, struct dp_packet **pkts,
>               }
>           }
>       } while (cnt);
> -    rte_spinlock_unlock(&vhost_dev->vhost_tx_lock);
> +
> +    if (vhost_dev->txq_needs_locking) {
> +        rte_spinlock_unlock(&vhost_dev->tx_q[qid].tx_lock);
> +    }
>
>       rte_spinlock_lock(&vhost_dev->stats_lock);
>       vhost_dev->stats.tx_packets += (total_pkts - cnt);
> @@ -1116,7 +1124,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet **pkts,
>       }
>
>       if (dev->type == DPDK_DEV_VHOST) {
> -        __netdev_dpdk_vhost_send(netdev, (struct dp_packet **) mbufs, newcnt, true);
> +        __netdev_dpdk_vhost_send(netdev, qid, (struct dp_packet **) mbufs, newcnt, true);
>       } else {
>           dpdk_queue_pkts(dev, qid, mbufs, newcnt);
>           dpdk_queue_flush(dev, qid);
> @@ -1128,7 +1136,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet **pkts,
>   }
>
>   static int
> -netdev_dpdk_vhost_send(struct netdev *netdev, int qid OVS_UNUSED, struct dp_packet **pkts,
> +netdev_dpdk_vhost_send(struct netdev *netdev, int qid, struct dp_packet **pkts,
>                    int cnt, bool may_steal)
>   {
>       if (OVS_UNLIKELY(pkts[0]->source != DPBUF_DPDK)) {
> @@ -1141,7 +1149,7 @@ netdev_dpdk_vhost_send(struct netdev *netdev, int qid OVS_UNUSED, struct dp_pack
>               }
>           }
>       } else {
> -        __netdev_dpdk_vhost_send(netdev, pkts, cnt, may_steal);
> +        __netdev_dpdk_vhost_send(netdev, qid, pkts, cnt, may_steal);
>       }
>       return 0;
>   }
> @@ -1656,7 +1664,18 @@ new_device(struct virtio_net *dev)
>       /* Add device to the vhost port with the same name as that passed down. */
>       LIST_FOR_EACH(netdev, list_node, &dpdk_list) {
>           if (strncmp(dev->ifname, netdev->vhost_id, IF_NAME_SZ) == 0) {
> +            int qp_num = rte_vhost_qp_num_get(dev);
Hi Flavio.

rte_vhost_qp_num_get() is in the multiple queue patch for upstream DPDK, 
referenced above, http://dpdk.org/ml/archives/dev/2015-June/019345.html. 
It gets the max number of virt queues for the device or 0. Is this 
unnecessary locking of the netdev dev, for each queue associated with 
the device? Should the test for qp_num below be before the netdev lock?
>               ovs_mutex_lock(&netdev->mutex);
> +            if (qp_num != netdev->real_n_rxq) {
> +                VLOG_INFO("vHost Device '%s' (%ld) can't be added - "
> +                          "unmatched number of queues %d and %d",
> +                          dev->ifname, dev->device_fh, qp_num,
> +                          netdev->real_n_rxq);
> +                ovs_mutex_unlock(&netdev->mutex);
> +                ovs_mutex_unlock(&dpdk_mutex);
> +                return -1;
> +            }
> +
>               ovsrcu_set(&netdev->virtio_dev, dev);
>               ovs_mutex_unlock(&netdev->mutex);
>               exists = true;
>




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