[dpdk-dev,5/5] virtio: optimize transmit enqueue
Commit Message
All the error checks in virtqueue_enqueue_xmit are already done
by the caller. Therefore they can be removed to improve performance.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
drivers/net/virtio/virtio_rxtx.c | 23 ++---------------------
1 file changed, 2 insertions(+), 21 deletions(-)
Comments
On 10/19/2015 1:16 PM, Stephen Hemminger wrote:
> All the error checks in virtqueue_enqueue_xmit are already done
> by the caller. Therefore they can be removed to improve performance.
>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Exactly the same thought as i commented in previous patch. We should
remove unnecessary checks as caller ensures they will pass.
We need check whether we need recheck "need" again after
virtio_xmit_cleanup for the previous indirect patch.
Acked-by: Huawei Xie <huawei.xie@intel.com>
> ---
> drivers/net/virtio/virtio_rxtx.c | 23 ++---------------------
> 1 file changed, 2 insertions(+), 21 deletions(-)
>
>
@@ -198,7 +198,7 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
return 0;
}
-static int
+static inline void
virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
uint16_t needed, int use_indirect, int can_push)
{
@@ -209,14 +209,7 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
uint16_t head_size = txvq->hw->vtnet_hdr_size;
unsigned long offs;
- if (unlikely(txvq->vq_free_cnt == 0))
- return -ENOSPC;
- if (unlikely(txvq->vq_free_cnt < needed))
- return -EMSGSIZE;
head_idx = txvq->vq_desc_head_idx;
- if (unlikely(head_idx >= txvq->vq_nentries))
- return -EFAULT;
-
idx = head_idx;
dxp = &txvq->vq_descx[idx];
dxp->cookie = (void *)cookie;
@@ -267,8 +260,6 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie,
txvq->vq_desc_tail_idx = idx;
txvq->vq_free_cnt = (uint16_t)(txvq->vq_free_cnt - needed);
vq_update_avail_ring(txvq, head_idx);
-
- return 0;
}
static inline struct rte_mbuf *
@@ -828,17 +819,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
}
/* Enqueue Packet buffers */
- error = virtqueue_enqueue_xmit(txvq, txm, slots,
- use_indirect, can_push);
- if (unlikely(error)) {
- if (error == ENOSPC)
- PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
- else if (error == EMSGSIZE)
- PMD_TX_LOG(ERR, "virtqueue_enqueue Free count < 1");
- else
- PMD_TX_LOG(ERR, "virtqueue_enqueue error: %d", error);
- break;
- }
+ virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect, can_push);
txvq->bytes += txm->pkt_len;
++txvq->packets;
}