From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id E7226A0524; Tue, 1 Jun 2021 09:57:39 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id D56DA4111C; Tue, 1 Jun 2021 09:57:39 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mails.dpdk.org (Postfix) with ESMTP id 49A7E41104 for ; Tue, 1 Jun 2021 09:57:38 +0200 (CEST) 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 C2C001FB; Tue, 1 Jun 2021 00:57:37 -0700 (PDT) Received: from net-arm-n1amp-01.shanghai.arm.com (net-arm-n1amp-01.shanghai.arm.com [10.169.210.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A80373F73D; Tue, 1 Jun 2021 00:57:34 -0700 (PDT) From: Ruifeng Wang To: jerinj@marvell.com, hemant.agrawal@nxp.com, ferruh.yigit@intel.com, thomas@monjalon.net, david.marchand@redhat.com Cc: dev@dpdk.org, nd@arm.com, honnappa.nagarahalli@arm.com, Ruifeng Wang , Ola Liljedahl Date: Tue, 1 Jun 2021 07:56:53 +0000 Message-Id: <20210601075653.84927-4-ruifeng.wang@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210601075653.84927-1-ruifeng.wang@arm.com> References: <20210318102550.59265-1-ruifeng.wang@arm.com> <20210601075653.84927-1-ruifeng.wang@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH v2 3/3] examples/l3fwd: eliminate unnecessary reloads in loop X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 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" Number of rx queue and number of rx port in lcore config are constants during the period of l3 forward application running. But compiler has no this information. Copied values from lcore config to local variables and used the local variables for iteration. Compiler can see that the local variables are not changed, so qconf reloads at each iteration can be eliminated. The change showed 1.8% performance uplift in single core, single port, single queue test on N1SDP platform with MLX5 NIC. Signed-off-by: Ruifeng Wang Reviewed-by: Ola Liljedahl Reviewed-by: Honnappa Nagarahalli --- examples/l3fwd/l3fwd_lpm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/examples/l3fwd/l3fwd_lpm.c b/examples/l3fwd/l3fwd_lpm.c index 427c72b1d2..ff1c18a442 100644 --- a/examples/l3fwd/l3fwd_lpm.c +++ b/examples/l3fwd/l3fwd_lpm.c @@ -154,14 +154,16 @@ lpm_main_loop(__rte_unused void *dummy) lcore_id = rte_lcore_id(); qconf = &lcore_conf[lcore_id]; - if (qconf->n_rx_queue == 0) { + const uint16_t n_rx_q = qconf->n_rx_queue; + const uint16_t n_tx_p = qconf->n_tx_port; + if (n_rx_q == 0) { RTE_LOG(INFO, L3FWD, "lcore %u has nothing to do\n", lcore_id); return 0; } RTE_LOG(INFO, L3FWD, "entering main loop on lcore %u\n", lcore_id); - for (i = 0; i < qconf->n_rx_queue; i++) { + for (i = 0; i < n_rx_q; i++) { portid = qconf->rx_queue_list[i].port_id; queueid = qconf->rx_queue_list[i].queue_id; @@ -181,7 +183,7 @@ lpm_main_loop(__rte_unused void *dummy) diff_tsc = cur_tsc - prev_tsc; if (unlikely(diff_tsc > drain_tsc)) { - for (i = 0; i < qconf->n_tx_port; ++i) { + for (i = 0; i < n_tx_p; ++i) { portid = qconf->tx_port_id[i]; if (qconf->tx_mbufs[portid].len == 0) continue; @@ -197,7 +199,7 @@ lpm_main_loop(__rte_unused void *dummy) /* * Read packet from RX queues */ - for (i = 0; i < qconf->n_rx_queue; ++i) { + for (i = 0; i < n_rx_q; ++i) { portid = qconf->rx_queue_list[i].port_id; queueid = qconf->rx_queue_list[i].queue_id; nb_rx = rte_eth_rx_burst(portid, queueid, pkts_burst, -- 2.25.1