diff options
authorGavin Hu <>2019-08-13 18:43:30 +0800
committerFerruh Yigit <>2019-09-03 17:12:37 +0200
commit78b50591c8e7ae3d010e8f4005e0e95c17800941 (patch)
parentceadf1a405d9951c6d15ed27e010f5b1a80dbdf5 (diff)
net/i40e: remove memory barrier from NEON Rx
For x86, the descriptors needs to be loaded in order, so in between two descriptors loading, there is a compiler barrier in place.[1] For aarch64, a patch [2] is in place to survive with discontinuous DD bits, the barriers can be removed to take full advantage of out-of-order execution. 50% performance gain in the RFC2544 NDR test was measured on ThunderX2. 12.50% performance gain in the RFC2544 NDR test was measured on Ampere eMAG80 platform. [1] [2] Fixes: ae0eb310f253 ("net/i40e: implement vector PMD for ARM") Cc: Signed-off-by: Gavin Hu <> Reviewed-by: Ruifeng Wang <> Reviewed-by: Steve Capper <>
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/net/i40e/i40e_rxtx_vec_neon.c b/drivers/net/i40e/i40e_rxtx_vec_neon.c
index 83572ef..5555e9b 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_neon.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c
@@ -285,7 +285,6 @@ _recv_raw_pkts_vec(struct i40e_rx_queue *rxq, struct rte_mbuf **rx_pkts,
/* Read desc statuses backwards to avoid race condition */
/* A.1 load 4 pkts desc */
descs[3] = vld1q_u64((uint64_t *)(rxdp + 3));
- rte_rmb();
/* B.2 copy 2 mbuf point into rx_pkts */
vst1q_u64((uint64_t *)&rx_pkts[pos], mbp1);