| Message ID | 1484722923-7698-3-git-send-email-jasowang@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jan 18, 2017 at 03:02:02PM +0800, Jason Wang wrote: > This patch tries to utilize tuntap rx batching by peeking the tx > virtqueue during transmission, if there's more available buffers in > the virtqueue, set MSG_MORE flag for a hint for backend (e.g tuntap) > to batch the packets. > > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> > Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> > --- > drivers/vhost/net.c | 23 ++++++++++++++++++++--- > 1 file changed, 20 insertions(+), 3 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 5dc3465..c42e9c3 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -351,6 +351,15 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net, > return r; > } > > +static bool vhost_exceeds_maxpend(struct vhost_net *net) > +{ > + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; > + struct vhost_virtqueue *vq = &nvq->vq; > + > + return (nvq->upend_idx + vq->num - VHOST_MAX_PEND) % UIO_MAXIOV > + == nvq->done_idx; > +} > + > /* Expects to be always run from workqueue - which acts as > * read-size critical section for our kind of RCU. */ > static void handle_tx(struct vhost_net *net) > @@ -394,8 +403,7 @@ static void handle_tx(struct vhost_net *net) > /* If more outstanding DMAs, queue the work. > * Handle upend_idx wrap around > */ > - if (unlikely((nvq->upend_idx + vq->num - VHOST_MAX_PEND) > - % UIO_MAXIOV == nvq->done_idx)) > + if (unlikely(vhost_exceeds_maxpend(net))) > break; > > head = vhost_net_tx_get_vq_desc(net, vq, vq->iov, > @@ -454,6 +462,16 @@ static void handle_tx(struct vhost_net *net) > msg.msg_control = NULL; > ubufs = NULL; > } > + > + total_len += len; > + if (total_len < VHOST_NET_WEIGHT && > + !vhost_vq_avail_empty(&net->dev, vq) && > + likely(!vhost_exceeds_maxpend(net))) { > + msg.msg_flags |= MSG_MORE; > + } else { > + msg.msg_flags &= ~MSG_MORE; > + } > + > /* TODO: Check specific error and bomb out unless ENOBUFS? */ > err = sock->ops->sendmsg(sock, &msg, len); > if (unlikely(err < 0)) { > @@ -472,7 +490,6 @@ static void handle_tx(struct vhost_net *net) > vhost_add_used_and_signal(&net->dev, vq, head, 0); > else > vhost_zerocopy_signal_used(net, vq); > - total_len += len; > vhost_net_tx_packet(net); > if (unlikely(total_len >= VHOST_NET_WEIGHT)) { > vhost_poll_queue(&vq->poll); > -- > 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 5dc3465..c42e9c3 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -351,6 +351,15 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net, return r; } +static bool vhost_exceeds_maxpend(struct vhost_net *net) +{ + struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; + struct vhost_virtqueue *vq = &nvq->vq; + + return (nvq->upend_idx + vq->num - VHOST_MAX_PEND) % UIO_MAXIOV + == nvq->done_idx; +} + /* Expects to be always run from workqueue - which acts as * read-size critical section for our kind of RCU. */ static void handle_tx(struct vhost_net *net) @@ -394,8 +403,7 @@ static void handle_tx(struct vhost_net *net) /* If more outstanding DMAs, queue the work. * Handle upend_idx wrap around */ - if (unlikely((nvq->upend_idx + vq->num - VHOST_MAX_PEND) - % UIO_MAXIOV == nvq->done_idx)) + if (unlikely(vhost_exceeds_maxpend(net))) break; head = vhost_net_tx_get_vq_desc(net, vq, vq->iov, @@ -454,6 +462,16 @@ static void handle_tx(struct vhost_net *net) msg.msg_control = NULL; ubufs = NULL; } + + total_len += len; + if (total_len < VHOST_NET_WEIGHT && + !vhost_vq_avail_empty(&net->dev, vq) && + likely(!vhost_exceeds_maxpend(net))) { + msg.msg_flags |= MSG_MORE; + } else { + msg.msg_flags &= ~MSG_MORE; + } + /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(sock, &msg, len); if (unlikely(err < 0)) { @@ -472,7 +490,6 @@ static void handle_tx(struct vhost_net *net) vhost_add_used_and_signal(&net->dev, vq, head, 0); else vhost_zerocopy_signal_used(net, vq); - total_len += len; vhost_net_tx_packet(net); if (unlikely(total_len >= VHOST_NET_WEIGHT)) { vhost_poll_queue(&vq->poll);