[dpdk-dev] [PATCH v2 1/6] vhost: rewrite enqueue

[Yuanhan Liu]

On Thu, Aug 18, 2016 at 02:33:06AM -0400, Zhihong Wang wrote:
> This patch implements the vhost logic from scratch into a single function
> designed for high performance and better maintainability.
> 
> Signed-off-by: Zhihong Wang <zhihong.wang at intel.com>
> ---
>  lib/librte_vhost/vhost_rxtx.c | 212 ++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 205 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 08a73fd..8e6d782 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -91,7 +91,7 @@ is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t qp_nb)
>  	return (is_tx ^ (idx & 1)) == 0 && idx < qp_nb * VIRTIO_QNUM;
>  }
>  
> -static void
> +static inline void __attribute__((always_inline))
>  virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
>  {
>  	if (m_buf->ol_flags & PKT_TX_L4_MASK) {
> @@ -533,19 +533,217 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
>  	return pkt_idx;
>  }
>  
> +static inline uint32_t __attribute__((always_inline))
> +loop_check(struct vhost_virtqueue *vq, uint16_t avail_idx, uint32_t pkt_left)
> +{
> +	if (pkt_left == 0 || avail_idx == vq->last_used_idx)
> +		return 1;
> +
> +	return 0;
> +}

Hmmm, I don't see any benifit from making such simple check into a
function.

> +static inline uint32_t __attribute__((always_inline))
> +enqueue_packet(struct virtio_net *dev, struct vhost_virtqueue *vq,
> +		uint16_t avail_idx, struct rte_mbuf *mbuf,
> +		uint32_t is_mrg_rxbuf)
> +{
> +	struct virtio_net_hdr_mrg_rxbuf *virtio_hdr;
> +	struct vring_desc *desc;
> +	uint64_t desc_host_write_addr = 0;
> +	uint32_t desc_chain_head = 0;
> +	uint32_t desc_chain_len = 0;
> +	uint32_t desc_current = 0;
> +	uint32_t desc_write_offset = 0;
> +	uint32_t mbuf_len = 0;
> +	uint32_t mbuf_len_left = 0;
> +	uint32_t copy_len = 0;

The dequeue function uses var like desc_addr, desc_avail, desc_offset,
mbuf_avail, ..., I see no reason to use something different here. This
breaks the code consistency. Besides that, var name like desc_host_write_addr
looks redundant; desc_addr is much cleaner.

	--yliu