[dpdk-dev] [RFC 10/29] vhost: prefetch desc
Tiwei Bie
tiwei.bie at intel.com
Wed Jun 21 04:57:46 CEST 2017
From: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
---
lib/librte_vhost/virtio_net.c | 36 +++++++++++++++++++++++++++++-------
1 file changed, 29 insertions(+), 7 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index c9e466f..b4d9031 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -974,10 +974,10 @@ mbuf_is_consumed(struct rte_mbuf *m)
return true;
}
-static inline uint16_t
+static inline uint16_t __attribute__((always_inline))
dequeue_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
struct rte_mempool *mbuf_pool, struct rte_mbuf *m,
- struct vring_desc_1_1 *descs)
+ struct vring_desc_1_1 *descs, uint16_t *desc_idx)
{
struct vring_desc_1_1 *desc;
uint64_t desc_addr;
@@ -986,7 +986,7 @@ dequeue_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
uint32_t cpy_len;
struct rte_mbuf *cur = m, *prev = m;
struct virtio_net_hdr *hdr = NULL;
- uint16_t head_idx = vq->last_used_idx;
+ uint16_t head_idx = *desc_idx;
desc = &descs[(head_idx++) & (vq->size - 1)];
if (unlikely((desc->len < dev->vhost_hlen)) ||
@@ -1114,7 +1114,7 @@ dequeue_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
if (hdr)
vhost_dequeue_offload(hdr, m);
- vq->last_used_idx = head_idx;
+ *desc_idx = head_idx;
return 0;
}
@@ -1128,11 +1128,32 @@ vhost_dequeue_burst_1_1(struct virtio_net *dev, struct vhost_virtqueue *vq,
uint16_t idx;
struct vring_desc_1_1 *desc = vq->desc_1_1;
uint16_t head_idx = vq->last_used_idx;
+ struct vring_desc_1_1 desc_cached[64];
+ uint16_t desc_idx = 0;
+
+ idx = vq->last_used_idx & (vq->size - 1);
+ if (!(desc[idx].flags & DESC_HW))
+ return 0;
count = RTE_MIN(MAX_PKT_BURST, count);
+
+ {
+ uint16_t size = vq->size - idx;
+ if (size >= 64)
+ rte_memcpy(&desc_cached[0], &desc[idx], 64 * sizeof(struct vring_desc_1_1));
+ else {
+ rte_memcpy(&desc_cached[0], &desc[idx], size * sizeof(struct vring_desc_1_1));
+ rte_memcpy(&desc_cached[size], &desc[0], (64 - size) * sizeof(struct vring_desc_1_1));
+ }
+ }
+
+ //for (i = 0; i < 64; i++) {
+ // idx = (vq->last_used_idx + i) & (vq->size - 1);
+ // desc_cached[i] = desc[idx];
+ //}
+
for (i = 0; i < count; i++) {
- idx = vq->last_used_idx & (vq->size - 1);
- if (!(desc[idx].flags & DESC_HW))
+ if (!(desc_cached[desc_idx].flags & DESC_HW))
break;
pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
@@ -1142,9 +1163,10 @@ vhost_dequeue_burst_1_1(struct virtio_net *dev, struct vhost_virtqueue *vq,
break;
}
- dequeue_desc(dev, vq, mbuf_pool, pkts[i], desc);
+ dequeue_desc(dev, vq, mbuf_pool, pkts[i], desc_cached, &desc_idx);
}
+ vq->last_used_idx += desc_idx;
if (likely(i)) {
for (idx = 1; idx < (uint16_t)(vq->last_used_idx - head_idx); idx++) {
desc[(idx + head_idx) & (vq->size - 1)].flags = 0;
--
2.7.4
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