[dpdk-dev] [PATCH] vhost: Only access header if offloading is supported in dequeue path
Maxime Coquelin
maxime.coquelin at redhat.com
Thu Oct 6 19:06:11 CEST 2016
On 10/06/2016 07:00 PM, Maxime Coquelin wrote:
> If offloading features are not negotiated, parsing the virtio header
> is not needed.
>
> Micro-benchmark with testpmd shows that the gain is +4% with indirect
> descriptors, +1% when using direct descriptors.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
> lib/librte_vhost/virtio_net.c | 47 ++++++++++++++++++++++++++++++++-----------
> 1 file changed, 35 insertions(+), 12 deletions(-)
>
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index a59c39b..5d51693 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -548,6 +548,18 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
> return virtio_dev_rx(dev, queue_id, pkts, count);
> }
>
> +static inline bool
> +virtio_net_with_host_offload(struct virtio_net *dev)
> +{
> + if (dev->features &
> + (VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_ECN |
> + VIRTIO_NET_F_HOST_TSO4 | VIRTIO_NET_F_HOST_TSO6 |
> + VIRTIO_NET_F_HOST_UFO))
> + return true;
> +
> + return false;
> +}
> +
> static void
> parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
> {
> @@ -600,6 +612,9 @@ vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
> void *l4_hdr = NULL;
> struct tcp_hdr *tcp_hdr = NULL;
>
> + if (hdr->flags == 0 || hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
> + return;
> +
Oops, just noticed I forgot to amend a fix I did.
Of course, the above test should be:
if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
It will be fixed in the v2.
Regards,
Maxime
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