[dpdk-dev] [RFC PATCH 08/11] xxx: batch the desc_hw update?
Jens Freimann
jfreiman at redhat.com
Fri May 5 15:57:19 CEST 2017
From: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Conflicts:
lib/librte_vhost/virtio_net.c
---
drivers/net/virtio/virtio_rxtx_1.1.c | 18 ++++++++++--------
lib/librte_vhost/virtio_net.c | 17 ++++++++++-------
2 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/drivers/net/virtio/virtio_rxtx_1.1.c b/drivers/net/virtio/virtio_rxtx_1.1.c
index e47a346..05f9dc7 100644
--- a/drivers/net/virtio/virtio_rxtx_1.1.c
+++ b/drivers/net/virtio/virtio_rxtx_1.1.c
@@ -89,7 +89,7 @@
}
static inline void
-virtio_xmit(struct virtnet_tx *txvq, struct rte_mbuf *mbuf)
+virtio_xmit(struct virtnet_tx *txvq, struct rte_mbuf *mbuf, int first_mbuf)
{
struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
struct virtqueue *vq = txvq->vq;
@@ -105,6 +105,8 @@
RTE_PTR_DIFF(&txr[idx].tx_hdr, txr);
desc[idx].len = vq->hw->vtnet_hdr_size;
desc[idx].flags = VRING_DESC_F_NEXT;
+ if (!first_mbuf)
+ desc[idx].flags |= DESC_HW;
do {
idx = (vq->vq_avail_idx++) & (vq->vq_nentries - 1);
@@ -115,12 +117,6 @@
desc[idx].flags &= ~VRING_DESC_F_NEXT;
- /*
- * update the head last, so that when the host saw such flag
- * is set, it means all others in the same chain is also set
- */
- rte_smp_wmb();
- desc[head_idx].flags |= DESC_HW;
}
uint16_t
@@ -129,6 +125,7 @@
struct virtnet_tx *txvq = tx_queue;
struct virtqueue *vq = txvq->vq;
uint16_t i;
+ uint16_t head_idx = vq->vq_avail_idx;
if (unlikely(nb_pkts < 1))
return nb_pkts;
@@ -148,10 +145,15 @@
}
}
- virtio_xmit(txvq, txm);
+ virtio_xmit(txvq, txm, i == 0);
txvq->stats.bytes += txm->pkt_len;
}
+ if (likely(i)) {
+ rte_smp_wmb();
+ vq->vq_ring.desc_1_1[head_idx & (vq->vq_nentries - 1)].flags |= DESC_HW;
+ }
+
txvq->stats.packets += i;
txvq->stats.errors += nb_pkts - i;
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index df88e31..c9e466f 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1009,9 +1009,6 @@ static inline bool __attribute__((always_inline))
*/
if (likely((desc->len == dev->vhost_hlen) &&
(desc->flags & VRING_DESC_F_NEXT) != 0)) {
- rte_smp_wmb();
- desc->flags = 0;
-
desc = &descs[(head_idx++) & (vq->size - 1)];
if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
return -1;
@@ -1072,8 +1069,6 @@ static inline bool __attribute__((always_inline))
if ((desc->flags & VRING_DESC_F_NEXT) == 0)
break;
- rte_smp_wmb();
- desc->flags = 0;
desc = &descs[(head_idx++) & (vq->size - 1)];
if (unlikely(desc->flags & VRING_DESC_F_INDIRECT))
return -1;
@@ -1112,8 +1107,6 @@ static inline bool __attribute__((always_inline))
mbuf_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
}
}
- rte_smp_wmb();
- desc->flags = 0;
prev->data_len = mbuf_offset;
m->pkt_len += mbuf_offset;
@@ -1134,7 +1127,9 @@ static inline bool __attribute__((always_inline))
uint16_t i;
uint16_t idx;
struct vring_desc_1_1 *desc = vq->desc_1_1;
+ uint16_t head_idx = vq->last_used_idx;
+ count = RTE_MIN(MAX_PKT_BURST, count);
for (i = 0; i < count; i++) {
idx = vq->last_used_idx & (vq->size - 1);
if (!(desc[idx].flags & DESC_HW))
@@ -1150,6 +1145,14 @@ static inline bool __attribute__((always_inline))
dequeue_desc(dev, vq, mbuf_pool, pkts[i], desc);
}
+ 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;
+ }
+ rte_smp_wmb();
+ desc[head_idx & (vq->size - 1)].flags = 0;
+ }
+
return i;
}
--
1.8.3.1
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