On Tue, Feb 01, 2011 at 03:07:38PM -0800, Sridhar Samudrala wrote: > On Tue, 2011-02-01 at 17:52 +0200, Michael S. Tsirkin wrote: > > OK, so thinking about it more, maybe the issue is this: > > tx becomes full. We process one request and interrupt the guest, > > then it adds one request and the queue is full again. > > > > Maybe the following will help it stabilize? By default with it we will > > only interrupt when we see an empty ring. > > Which is liklely too much: pls try other values > > in the middle: e.g. make bufs half the ring, > > or bytes some small value like half ring * 200, or packets some > > small value etc. > > > > Set any one parameter to 0 to get current > > behaviour (interrupt immediately when enabled). > > > > Warning: completely untested. > > > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > > > > --- > > > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > > index aac05bc..6769cdc 100644 > > --- a/drivers/vhost/net.c > > +++ b/drivers/vhost/net.c > > @@ -32,6 +32,13 @@ > > * Using this limit prevents one virtqueue from starving others. */ > > #define VHOST_NET_WEIGHT 0x80000 > > > > +int tx_bytes_coalesce = 1000000000; > > +module_param(tx_bytes_coalesce, int, 0644); > > +int tx_bufs_coalesce = 1000000000; > > +module_param(tx_bufs_coalesce, int, 0644); > > +int tx_packets_coalesce = 1000000000; > > +module_param(tx_packets_coalesce, int, 0644); > > + > > enum { > > VHOST_NET_VQ_RX = 0, > > VHOST_NET_VQ_TX = 1, > > @@ -127,6 +134,9 @@ static void handle_tx(struct vhost_net *net) > > int err, wmem; > > size_t hdr_size; > > struct socket *sock; > > + int bytes_coalesced = 0; > > + int bufs_coalesced = 0; > > + int packets_coalesced = 0; > > > > /* TODO: check that we are running from vhost_worker? */ > > sock = rcu_dereference_check(vq->private_data, 1); > > @@ -196,14 +206,26 @@ static void handle_tx(struct vhost_net *net) > > if (err != len) > > pr_debug("Truncated TX packet: " > > " len %d != %zd\n", err, len); > > - vhost_add_used_and_signal(&net->dev, vq, head, 0); > > total_len += len; > > + packets_coalesced += 1; > > + bytes_coalesced += len; > > + bufs_coalesced += out; > > + if (unlikely(packets_coalesced > tx_packets_coalesce || > > + bytes_coalesced > tx_bytes_coalesce || > > + bufs_coalesced > tx_bufs_coalesce)) > > + vhost_add_used_and_signal(&net->dev, vq, head, 0); > > I think the counters that exceed the limits need to be reset to 0 here. > Otherwise we keep signaling for every buffer once we hit this condition. > > Thanks > Sridhar
Correct, good catch. > > + else > > + vhost_add_used(vq, head, 0); > > if (unlikely(total_len >= VHOST_NET_WEIGHT)) { > > vhost_poll_queue(&vq->poll); > > break; > > } > > } > > > > + if (likely(packets_coalesced && > > + bytes_coalesced && > > + bufs_coalesced)) > > + vhost_signal(&net->dev, vq); > > mutex_unlock(&vq->mutex); > > } > > > > -- > > To unsubscribe from this list: send the line "unsubscribe netdev" in > > the body of a message to majord...@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html