Optimize vhost device rx function by separate descriptors, no-chained
and direct descriptors will be handled by burst and other will be
handled one by one as before. Pre-fetch descriptors in next two cache
lines as hardware will load two cache line data automatically.
Signed-off-by: Marvin Liu <yong....@intel.com>
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 8d09e1611..269ec8a43 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -769,64 +769,6 @@ fill_vec_buf_packed(struct virtio_net *dev, struct
vhost_virtqueue *vq,
return 0;
}
-/*
- * Returns -1 on fail, 0 on success
- */
-static inline int
-reserve_avail_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
- uint32_t size, struct buf_vector *buf_vec,
- uint16_t *nr_vec, uint16_t *num_buffers,
- uint16_t *nr_descs)
-{
- uint16_t avail_idx;
- uint16_t vec_idx = 0;
- uint16_t max_tries, tries = 0;
-
- uint16_t buf_id = 0;
- uint32_t len = 0;
- uint16_t desc_count;
-
- *num_buffers = 0;
- avail_idx = vq->last_avail_idx;
-
- if (rxvq_is_mergeable(dev))
- max_tries = vq->size - 1;
- else
- max_tries = 1;
-
- while (size > 0) {
- /*
- * if we tried all available ring items, and still
- * can't get enough buf, it means something abnormal
- * happened.
- */
- if (unlikely(++tries > max_tries))
- return -1;
-
- if (unlikely(fill_vec_buf_packed(dev, vq,
- avail_idx, &desc_count,
- buf_vec, &vec_idx,
- &buf_id, &len,
- VHOST_ACCESS_RW) < 0))
- return -1;
-
- len = RTE_MIN(len, size);
- update_shadow_packed(vq, buf_id, len, desc_count);
- size -= len;
-
- avail_idx += desc_count;
- if (avail_idx >= vq->size)
- avail_idx -= vq->size;
-
- *nr_descs += desc_count;
- *num_buffers += 1;
- }
-
- *nr_vec = vec_idx;
-
- return 0;
-}
-
static __rte_noinline void
copy_vnet_hdr_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
struct buf_vector *buf_vec,
@@ -1120,7 +1062,7 @@ virtio_dev_rx_split(struct virtio_net *dev, struct
vhost_virtqueue *vq,
return pkt_idx;
}
-static __rte_unused uint16_t
+static __rte_always_inline uint16_t
virtio_dev_rx_burst_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
struct rte_mbuf **pkts)
{
@@ -1229,7 +1171,7 @@ virtio_dev_rx_burst_packed(struct virtio_net *dev, struct
vhost_virtqueue *vq,
return 0;
}
-static __rte_unused int16_t
+static __rte_always_inline int16_t
virtio_dev_rx_single_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
struct rte_mbuf *pkt)
{
@@ -1263,46 +1205,45 @@ virtio_dev_rx_packed(struct virtio_net *dev, struct
vhost_virtqueue *vq,
struct rte_mbuf **pkts, uint32_t count)
{
uint32_t pkt_idx = 0;
- uint16_t num_buffers;
- struct buf_vector buf_vec[BUF_VECTOR_MAX];
+ uint32_t pkt_num;
+ uint32_t remained = count;
+ uint16_t fetch_idx;
+ int ret;
+ struct vring_packed_desc *descs = vq->desc_packed;
- for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
- uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
- uint16_t nr_vec = 0;
- uint16_t nr_descs = 0;
+ do {
+ if ((vq->last_avail_idx & 0x7) == 0) {
+ fetch_idx = vq->last_avail_idx + 8;
+ rte_prefetch0((void *)(uintptr_t)&descs[fetch_idx]);
+ }
- if (unlikely(reserve_avail_buf_packed(dev, vq,
- pkt_len, buf_vec, &nr_vec,
- &num_buffers, &nr_descs) < 0)) {
- VHOST_LOG_DEBUG(VHOST_DATA,
- "(%d) failed to get enough desc from vring\n",
- dev->vid);
- vq->shadow_used_idx -= num_buffers;
- break;
+ if (remained >= PACKED_DESCS_BURST) {
+ ret = virtio_dev_rx_burst_packed(dev, vq, pkts);
+
+ if (!ret) {
+ pkt_num = PACKED_DESCS_BURST;
+ pkt_idx += pkt_num;
+ remained -= pkt_num;
+ continue;
+ }
}
- VHOST_LOG_DEBUG(VHOST_DATA, "(%d) current index %d | end index
%d\n",
- dev->vid, vq->last_avail_idx,
- vq->last_avail_idx + num_buffers);
+ pkt_num = virtio_dev_rx_single_packed(dev, vq, pkts[pkt_idx]);
- if (copy_mbuf_to_desc(dev, vq, pkts[pkt_idx],
- buf_vec, nr_vec,
- num_buffers) < 0) {
- vq->shadow_used_idx -= num_buffers;
+ if (pkt_num == 0)
break;
- }
- vq->last_avail_idx += nr_descs;
- if (vq->last_avail_idx >= vq->size) {
- vq->last_avail_idx -= vq->size;
- vq->avail_wrap_counter ^= 1;
- }
- }
+ pkt_idx += pkt_num;
+ remained -= pkt_num;
- do_data_copy_enqueue(dev, vq);
+ } while (pkt_idx < count);
+
+ if (pkt_idx) {
+ if (vq->shadow_used_idx) {
+ do_data_copy_enqueue(dev, vq);
+ flush_enqueue_shadow_packed(dev, vq);
+ }
- if (likely(vq->shadow_used_idx)) {
- flush_enqueue_shadow_packed(dev, vq);
vhost_vring_call_packed(dev, vq);
}
--
2.17.1
