On Fri, Sep 07, 2018 at 03:41:52PM +0800, Jason Wang wrote:
> > > @@ -556,10 +667,14 @@ static void handle_tx_copy(struct vhost_net *net,
> > > struct socket *sock)
> > > size_t len, total_len = 0;
> > > int err;
> > > int sent_pkts = 0;
> > > + bool bulking = (sock->sk->sk_sndbuf == INT_MAX);
> > What does bulking mean?
>
> The name is misleading, it means whether we can do batching. For simplicity,
> I disable batching is sndbuf is not INT_MAX.
But what does batching have to do with sndbuf?
> > > for (;;) {
> > > bool busyloop_intr = false;
> > > + if (nvq->done_idx == VHOST_NET_BATCH)
> > > + vhost_tx_batch(net, nvq, sock, &msg);
> > > +
> > > head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
> > > &busyloop_intr);
> > > /* On error, stop handling until the next kick. */
> > > @@ -577,14 +692,34 @@ static void handle_tx_copy(struct vhost_net *net,
> > > struct socket *sock)
> > > break;
> > > }
> > > - vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
> > > - vq->heads[nvq->done_idx].len = 0;
> > > -
> > > total_len += len;
> > > - if (tx_can_batch(vq, total_len))
> > > - msg.msg_flags |= MSG_MORE;
> > > - else
> > > - msg.msg_flags &= ~MSG_MORE;
> > > +
> > > + /* For simplicity, TX batching is only enabled if
> > > + * sndbuf is unlimited.
> > What if sndbuf changes while this processing is going on?
>
> We will get the correct sndbuf in the next run of handle_tx(). I think this
> is safe.
If it's safe why bother with special-casing INT_MAX?
--
MST
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