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Commit 29d40c90 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net/mlx4_en: Use prefetch in tx path 



mlx4_en_free_tx_desc() uses a prefetchw(&skb->users) to speed up
consume_skb()
prefetchw(&ring->tx_queue->dql) to speed up BQL update

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarAmir Vadai <amirv@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3d03641c

drivers/net/ethernet/mellanox/mlx4/en_tx.c

+9 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/mlx4/qp.h>

#include <linux/skbuff.h>

#include <linux/if_vlan.h>

#include <linux/prefetch.h>

#include <linux/vmalloc.h>

#include <linux/tcp.h>

#include <linux/ip.h>
@@ -267,6 +268,11 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv, 
	int nr_maps = tx_info->nr_maps;

	int i;



	/* We do not touch skb here, so prefetch skb->users location

	 * to speedup consume_skb()

	 */

	prefetchw(&skb->users);



	if (unlikely(timestamp)) {

		struct skb_shared_hwtstamps hwts;
@@ -385,6 +391,7 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, 
	if (!priv->port_up)

		return true;



	prefetchw(&ring->tx_queue->dql.limit);

	index = cons_index & size_mask;

	cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;

	ring_index = ring->cons & size_mask;
@@ -722,6 +729,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) 
		}

	}



	prefetchw(&ring->tx_queue->dql);



	/* Track current inflight packets for performance analysis */

	AVG_PERF_COUNTER(priv->pstats.inflight_avg,

			 (u32) (ring->prod - ring->cons - 1));