Re: [dpdk-dev] [PATCH 1/2] vhost: unify Rx mergeable and non-mergeable paths

[Maxime Coquelin]

On 05/28/2018 06:23 PM, Maxime Coquelin wrote:

@@ -602,7 +297,7 @@ reserve_avail_buf_mergeable(struct virtio_net *dev, struct 
vhost_virtqueue *vq,

Just notice I forgot to remove "mergeable" from the functions names here
and below. I'll fix this in next revision after having collected some
feedback.

  {
        uint16_t cur_idx;
        uint32_t vec_idx = 0;
-       uint16_t tries = 0;
+       uint16_t max_tries, tries = 0;

uint16_t head_idx = 0;

        uint16_t len = 0;
@@ -610,6 +305,11 @@ reserve_avail_buf_mergeable(struct virtio_net *dev, struct 
vhost_virtqueue *vq,
        *num_buffers = 0;
        cur_idx  = vq->last_avail_idx;

+ if (rxvq_is_mergeable(dev))

+               max_tries = vq->size;
+       else
+               max_tries = 1;
+
        while (size > 0) {
                if (unlikely(cur_idx == avail_head))
                        return -1;
@@ -630,7 +330,7 @@ reserve_avail_buf_mergeable(struct virtio_net *dev, struct 
vhost_virtqueue *vq,
                 * can't get enough buf, it means something abnormal
                 * happened.
                 */
-               if (unlikely(tries >= vq->size))
+               if (unlikely(tries > max_tries))
                        return -1;
        }

@@ -748,7 +448,9 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq, if (hdr_addr) {

                        virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
-                       ASSIGN_UNLESS_EQUAL(hdr->num_buffers, num_buffers);
+                       if (rxvq_is_mergeable(dev))
+                               ASSIGN_UNLESS_EQUAL(hdr->num_buffers,
+                                               num_buffers);

if (unlikely(hdr == &tmp_hdr)) {

                                uint64_t len;
@@ -923,10 +625,7 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
                return 0;
        }

- if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))

-               return virtio_dev_merge_rx(dev, queue_id, pkts, count);
-       else
-               return virtio_dev_rx(dev, queue_id, pkts, count);
+       return virtio_dev_merge_rx(dev, queue_id, pkts, count);
  }

static inline bool

-- 2.14.3