From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id D2DF6A056A; Fri, 6 Mar 2020 06:05:15 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 63D771BFDB; Fri, 6 Mar 2020 06:05:10 +0100 (CET) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id A11011BFDA; Fri, 6 Mar 2020 06:05:08 +0100 (CET) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2336430E; Thu, 5 Mar 2020 21:05:08 -0800 (PST) Received: from net-arm-thunderx2-04.shanghai.arm.com (net-arm-thunderx2-04.shanghai.arm.com [10.169.40.184]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 190B33F6CF; Thu, 5 Mar 2020 21:05:04 -0800 (PST) From: Gavin Hu 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 Date: Fri, 6 Mar 2020 13:04:25 +0800 Message-Id: <20200306050427.66114-2-gavin.hu@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200306050427.66114-1-gavin.hu@arm.com> References: <20200306050427.66114-1-gavin.hu@arm.com> Subject: [dpdk-dev] [PATCH v1 1/3] net/i40e: relax barrier in the Tx fastpath of vPMD X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" To keep ordering of mixed accesses, rte_cio is sufficient. The rte_io barrier 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: 4861cde46116 ("i40e: new poll mode driver") Cc: stable@dpdk.org Signed-off-by: Gavin Hu --- 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