[ovs-dev] [RFC] dpdk: support multiple queues in vhost
Flavio Leitner
fbl at sysclose.org
Thu Aug 6 17:40:00 UTC 2015
On Thu, Aug 06, 2015 at 12:39:29PM -0400, Thomas F Herbert wrote:
> 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?
It only compares the number of queues if the device is the
one we are looking for, so it happens only a single time, not per queue.
And the real_n_rxq is a property of the datapath which can change,
hence the need for the lock.
fbl
> > 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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