On Fri, May 17, 2019 at 05:06:12PM +0200, Maxime Coquelin wrote:
> Now that we have a single function to map the descriptors
> buffers, let's prefetch them there as it is the earliest
> place we can do it.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> lib/librte_vhost/virtio_net.c | 32 ++------------------------------
> 1 file changed, 2 insertions(+), 30 deletions(-)
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
@@ -286,6 +286,8 @@ map_one_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
if (unlikely(!desc_addr))
return -1;
+ rte_prefetch0((void *)(uintptr_t)desc_addr);
+
buf_vec[vec_id].buf_iova = desc_iova;
buf_vec[vec_id].buf_addr = desc_addr;
buf_vec[vec_id].buf_len = desc_chunck_len;
@@ -665,9 +667,6 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
buf_iova = buf_vec[vec_idx].buf_iova;
buf_len = buf_vec[vec_idx].buf_len;
- if (nr_vec > 1)
- rte_prefetch0((void *)(uintptr_t)buf_vec[1].buf_addr);
-
if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
error = -1;
goto out;
@@ -710,10 +709,6 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
buf_iova = buf_vec[vec_idx].buf_iova;
buf_len = buf_vec[vec_idx].buf_len;
- /* Prefetch next buffer address. */
- if (vec_idx + 1 < nr_vec)
- rte_prefetch0((void *)(uintptr_t)
- buf_vec[vec_idx + 1].buf_addr);
buf_offset = 0;
buf_avail = buf_len;
}
@@ -811,8 +806,6 @@ virtio_dev_rx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
break;
}
- rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr);
-
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);
@@ -860,8 +853,6 @@ virtio_dev_rx_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
break;
}
- rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr);
-
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);
@@ -1121,16 +1112,12 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
goto out;
}
- if (likely(nr_vec > 1))
- rte_prefetch0((void *)(uintptr_t)buf_vec[1].buf_addr);
-
if (virtio_net_with_host_offload(dev)) {
if (unlikely(buf_len < sizeof(struct virtio_net_hdr))) {
copy_vnet_hdr_from_desc(&tmp_hdr, buf_vec);
hdr = &tmp_hdr;
} else {
hdr = (struct virtio_net_hdr *)((uintptr_t)buf_addr);
- rte_prefetch0(hdr);
}
}
@@ -1160,9 +1147,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
buf_avail = buf_vec[vec_idx].buf_len - dev->vhost_hlen;
}
- rte_prefetch0((void *)(uintptr_t)
- (buf_addr + buf_offset));
-
PRINT_PACKET(dev,
(uintptr_t)(buf_addr + buf_offset),
(uint32_t)buf_avail, 0);
@@ -1228,14 +1212,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
buf_iova = buf_vec[vec_idx].buf_iova;
buf_len = buf_vec[vec_idx].buf_len;
- /*
- * Prefecth desc n + 1 buffer while
- * desc n buffer is processed.
- */
- if (vec_idx + 1 < nr_vec)
- rte_prefetch0((void *)(uintptr_t)
- buf_vec[vec_idx + 1].buf_addr);
-
buf_offset = 0;
buf_avail = buf_len;
@@ -1379,8 +1355,6 @@ virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
if (likely(dev->dequeue_zero_copy == 0))
update_shadow_used_ring_split(vq, head_idx, 0);
- rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr);
-
pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
if (unlikely(pkts[i] == NULL)) {
RTE_LOG(ERR, VHOST_DATA,
@@ -1490,8 +1464,6 @@ virtio_dev_tx_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
update_shadow_used_ring_packed(vq, buf_id, 0,
desc_count);
- rte_prefetch0((void *)(uintptr_t)buf_vec[0].buf_addr);
-
pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
if (unlikely(pkts[i] == NULL)) {
RTE_LOG(ERR, VHOST_DATA,