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From: Gavin Hu <gavin.hu@arm.com>
To: dev@dpdk.org
Cc: nd@arm.com, david.marchand@redhat.com, thomas@monjalon.net,
	jerinj@marvell.com, xiaolong.ye@intel.com,
	Honnappa.Nagarahalli@arm.com, ruifeng.wang@arm.com,
	phil.yang@arm.com, joyce.kong@arm.com, steve.capper@arm.com,
	stable@dpdk.org
Subject: [dpdk-dev] [PATCH v3 1/2] net/i40e: relax barrier in Tx fastpath for NEON vPMD
Date: Tue, 14 Apr 2020 00:40:24 +0800
Message-ID: <20200413164025.9751-2-gavin.hu@arm.com> (raw)
In-Reply-To: <20200413164025.9751-1-gavin.hu@arm.com>
In-Reply-To: <20200306050427.66114-1-gavin.hu@arm.com>

To keep ordering of mixed accesses, 'DMB OSH' is sufficient.
'DSB' inside the I40E_PCI_REG_WRITE is overkill.[1]

This patch fixes by replacing with just sufficient barriers in the
normal PMD and vPMD.

It showed 7% performance uplift on ThunderX2 and 4% on Arm N1SDP.
The test case is the RFC2544 zero-loss test running testpmd.

[1] http://inbox.dpdk.org/dev/CALBAE1M-ezVWCjqCZDBw+MMDEC4O9
qf0Kpn89EMdGDajepKoZQ@mail.gmail.com

Fixes: ae0eb310f253 ("net/i40e: implement vector PMD for ARM")
Cc: stable@dpdk.org

Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>
---
 drivers/net/i40e/i40e_rxtx_vec_neon.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/i40e/i40e_rxtx_vec_neon.c b/drivers/net/i40e/i40e_rxtx_vec_neon.c
index deb185fe2..4376d8911 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_neon.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c
@@ -72,8 +72,9 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
 	rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
 			     (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
 
+	rte_cio_wmb();
 	/* Update the tail pointer on the NIC */
-	I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+	I40E_PCI_REG_WRITE_RELAXED(rxq->qrx_tail, rx_id);
 }
 
 static inline void
@@ -564,7 +565,8 @@ i40e_xmit_fixed_burst_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
 
 	txq->tx_tail = tx_id;
 
-	I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	rte_cio_wmb();
+	I40E_PCI_REG_WRITE_RELAXED(txq->qtx_tail, tx_id);
 
 	return nb_pkts;
 }
-- 
2.17.1


  parent reply	other threads:[~2020-04-13 16:41 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-06  5:04 [dpdk-dev] [PATCH v1 0/3] i40e vPMD optimization on aarch64 Gavin Hu
2020-03-06  5:04 ` [dpdk-dev] [PATCH v1 1/3] net/i40e: relax barrier in the Tx fastpath of vPMD Gavin Hu
2020-03-06  9:11   ` Jerin Jacob
2020-03-06  5:04 ` [dpdk-dev] [PATCH v1 2/3] net/i40e: restrict pointer aliasing for neon vec Gavin Hu
2020-03-06  5:04 ` [dpdk-dev] [PATCH v1 3/3] net/i40e: auto-vectorization to speed up Tx free Gavin Hu
2020-03-06  7:44   ` Jerin Jacob
2020-03-06  9:06     ` Thomas Monjalon
2020-03-07 15:03     ` Gavin Hu
2020-03-09  7:35       ` Jerin Jacob
2020-03-09  9:23         ` Gavin Hu
2020-04-13 15:56 ` [dpdk-dev] [PATCH v2 0/2] i40e NEON vPMD optimization on aarch64 Gavin Hu
2020-04-13 15:56 ` [dpdk-dev] [PATCH v2 1/2] net/i40e: relax barrier in Tx fastpath for NEON vPMD Gavin Hu
2020-04-13 15:56 ` [dpdk-dev] [PATCH v2 2/2] net/i40e: restrict pointer aliasing " Gavin Hu
2020-04-20 14:51   ` Ferruh Yigit
2020-04-21  9:51     ` Gavin Hu
2020-04-13 16:40 ` [dpdk-dev] [PATCH v3 0/2] i40e NEON vPMD optimization on aarch64 Gavin Hu
2020-04-15  6:50   ` Ye Xiaolong
2020-04-13 16:40 ` Gavin Hu [this message]
2020-04-13 16:40 ` [dpdk-dev] [PATCH v3 2/2] net/i40e: restrict pointer aliasing for NEON vPMD Gavin Hu

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