From: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Date: Fri, 27 Sep 2019 20:30:05 +0000 (+0530)
Subject: net/cxgbe: fix prefetch for non-coalesced Tx packets
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=b1df19e43e1d1415ab7fae119e672a2f3b8f39f0;p=dpdk.git

net/cxgbe: fix prefetch for non-coalesced Tx packets

Move prefetch code out of Tx coalesce path to allow prefetching for
non-coalesced Tx packets, as well.

Fixes: bf89cbedd2d9 ("cxgbe: optimize forwarding performance for 40G")
Cc: stable@dpdk.org

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
---

diff --git a/drivers/net/cxgbe/cxgbe_ethdev.c b/drivers/net/cxgbe/cxgbe_ethdev.c
index 7d7be69edd..5d74f8ba3b 100644
--- a/drivers/net/cxgbe/cxgbe_ethdev.c
+++ b/drivers/net/cxgbe/cxgbe_ethdev.c
@@ -67,6 +67,7 @@ uint16_t cxgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 	struct sge_eth_txq *txq = (struct sge_eth_txq *)tx_queue;
 	uint16_t pkts_sent, pkts_remain;
 	uint16_t total_sent = 0;
+	uint16_t idx = 0;
 	int ret = 0;
 
 	CXGBE_DEBUG_TX(adapter, "%s: txq = %p; tx_pkts = %p; nb_pkts = %d\n",
@@ -75,12 +76,16 @@ uint16_t cxgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 	t4_os_lock(&txq->txq_lock);
 	/* free up desc from already completed tx */
 	reclaim_completed_tx(&txq->q);
+	rte_prefetch0(rte_pktmbuf_mtod(tx_pkts[0], volatile void *));
 	while (total_sent < nb_pkts) {
 		pkts_remain = nb_pkts - total_sent;
 
 		for (pkts_sent = 0; pkts_sent < pkts_remain; pkts_sent++) {
-			ret = t4_eth_xmit(txq, tx_pkts[total_sent + pkts_sent],
-					  nb_pkts);
+			idx = total_sent + pkts_sent;
+			if ((idx + 1) < nb_pkts)
+				rte_prefetch0(rte_pktmbuf_mtod(tx_pkts[idx + 1],
+							volatile void *));
+			ret = t4_eth_xmit(txq, tx_pkts[idx], nb_pkts);
 			if (ret < 0)
 				break;
 		}
diff --git a/drivers/net/cxgbe/sge.c b/drivers/net/cxgbe/sge.c
index 641be96578..bf31902111 100644
--- a/drivers/net/cxgbe/sge.c
+++ b/drivers/net/cxgbe/sge.c
@@ -1154,7 +1154,6 @@ out_free:
 				txq->stats.mapping_err++;
 				goto out_free;
 			}
-			rte_prefetch0((volatile void *)addr);
 			return tx_do_packet_coalesce(txq, mbuf, cflits, adap,
 						     pi, addr, nb_pkts);
 		} else {