[dpdk-stable] patch 'net/mlx5: fix instruction hotspot on replenishing Rx buffer' has been queued to LTS release 18.11.1

[Kevin Traynor <ktraynor@redhat.com>]

Hi,

FYI, your patch has been queued to LTS release 18.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 03/22/19. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Kevin Traynor

---
From 40454190463981cc1c382a6470cd64970a4025c3 Mon Sep 17 00:00:00 2001
From: Yongseok Koh <yskoh@mellanox.com>
Date: Thu, 7 Mar 2019 18:07:55 -0800
Subject: [PATCH] net/mlx5: fix instruction hotspot on replenishing Rx buffer

[ backported from upstream commit 12d468a62bc19ca08ee9964dcb923f67f87fba7d ]

On replenishing Rx buffers for vectorized Rx, mbuf->buf_addr isn't needed
to be accessed as it is static and easily calculated from the mbuf address.
Accessing the mbuf content causes unnecessary load stall and it is worsened
on ARM.

Fixes: 545b884b1da3 ("net/mlx5: fix buffer address posting in SSE Rx")

Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>
---
 drivers/net/mlx5/mlx5_rxtx_vec.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rxtx_vec.h b/drivers/net/mlx5/mlx5_rxtx_vec.h
index fda7004e2..da447a63e 100644
--- a/drivers/net/mlx5/mlx5_rxtx_vec.h
+++ b/drivers/net/mlx5/mlx5_rxtx_vec.h
@@ -103,6 +103,10 @@ mlx5_rx_replenish_bulk_mbuf(struct mlx5_rxq_data *rxq, uint16_t n)
 	}
 	for (i = 0; i < n; ++i) {
-		wq[i].addr = rte_cpu_to_be_64((uintptr_t)elts[i]->buf_addr +
-					      RTE_PKTMBUF_HEADROOM);
+		uintptr_t buf_addr =
+			(uintptr_t)elts[i] + sizeof(struct rte_mbuf) +
+			rte_pktmbuf_priv_size(rxq->mp);
+
+		assert(buf_addr == (uintptr_t)elts[i]->buf_addr);
+		wq[i].addr = rte_cpu_to_be_64(buf_addr + RTE_PKTMBUF_HEADROOM);
 		/* If there's only one MR, no need to replace LKey in WQE. */
 		if (unlikely(mlx5_mr_btree_len(&rxq->mr_ctrl.cache_bh) > 1))
-- 
2.20.1