[dpdk-dev,v2,2/2] net/mlx5: change error-prone code on Tx path
Checks
Commit Message
In the main loop of mlx5_tx_burst(), poitners/indexes are advanced at the
beginning. Therefore, those should be rolled back if checking resource
availability fails and breaks the loop. And some of them are even
redundant.
Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
---
drivers/net/mlx5/mlx5_rxtx.c | 34 ++++++++++++----------------------
1 file changed, 12 insertions(+), 22 deletions(-)
@@ -538,7 +538,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
#endif
/* first_seg */
- buf = *(pkts++);
+ buf = *pkts;
segs_n = buf->nb_segs;
/*
* Make sure there is enough room to store this packet and
@@ -549,15 +549,13 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
break;
max -= segs_n;
--segs_n;
- if (!segs_n)
- --pkts_n;
if (unlikely(--max_wqe == 0))
break;
wqe = (volatile struct mlx5_wqe_v *)
tx_mlx5_wqe(txq, txq->wqe_ci);
rte_prefetch0(tx_mlx5_wqe(txq, txq->wqe_ci + 1));
- if (pkts_n > 1)
- rte_prefetch0(*pkts);
+ if (pkts_n - i > 1)
+ rte_prefetch0(*(pkts + 1));
addr = rte_pktmbuf_mtod(buf, uintptr_t);
length = DATA_LEN(buf);
ehdr = (((uint8_t *)addr)[1] << 8) |
@@ -569,14 +567,10 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
break;
/* Update element. */
(*txq->elts)[elts_head] = buf;
- elts_head = (elts_head + 1) & (elts_n - 1);
/* Prefetch next buffer data. */
- if (pkts_n > 1) {
- volatile void *pkt_addr;
-
- pkt_addr = rte_pktmbuf_mtod(*pkts, volatile void *);
- rte_prefetch0(pkt_addr);
- }
+ if (pkts_n - i > 1)
+ rte_prefetch0(
+ rte_pktmbuf_mtod(*(pkts + 1), volatile void *));
/* Should we enable HW CKSUM offload */
if (buf->ol_flags &
(PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM | PKT_TX_UDP_CKSUM)) {
@@ -679,10 +673,6 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
};
ds = 1;
total_length = 0;
- pkts--;
- pkts_n++;
- elts_head = (elts_head - 1) &
- (elts_n - 1);
k++;
goto next_wqe;
}
@@ -815,17 +805,17 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
naddr,
naddr >> 32,
};
- (*txq->elts)[elts_head] = buf;
elts_head = (elts_head + 1) & (elts_n - 1);
+ (*txq->elts)[elts_head] = buf;
++sg;
/* Advance counter only if all segs are successfully posted. */
- if (sg < segs_n) {
+ if (sg < segs_n)
goto next_seg;
- } else {
- --pkts_n;
+ else
j += sg;
- }
next_pkt:
+ elts_head = (elts_head + 1) & (elts_n - 1);
+ ++pkts;
++i;
/* Initialize known and common part of the WQE structure. */
if (tso) {
@@ -863,7 +853,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
/* Increment sent bytes counter. */
txq->stats.obytes += total_length;
#endif
- } while (pkts_n);
+ } while (i < pkts_n);
/* Take a shortcut if nothing must be sent. */
if (unlikely((i + k) == 0))
return 0;