From patchwork Mon Apr 15 09:48:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Barker X-Patchwork-Id: 13629730 X-Patchwork-Delegate: kuba@kernel.org Received: from relmlie5.idc.renesas.com (relmlor1.renesas.com [210.160.252.171]) by smtp.subspace.kernel.org (Postfix) with ESMTP id F050F5810D; Mon, 15 Apr 2024 09:48:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.160.252.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713174526; cv=none; b=N2kD3pDxcmIr0/LJyuze1oAE78MUESSGA0jbLMbkPHXIkTCrV/Q2Ec2suMgXTJVjgNXlYgD75UaJbDDiLT74i5JgvNc605I7xon7pOM9aVc6Euybxea/zJjaaFhUwg3VeJQTCoqpvCmBxnZ0x2804w0HtNMa01A6ALe1HD63RBs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713174526; c=relaxed/simple; bh=X6lYavWy79tCYcp+pVwRpetbT7q8jO8kWdKXbffGxXA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OtyREGeMgnr7F2nHvRZeNjElVwMD7+InGowBzAHh/UL/yPQPpYZVpfJpi6fTIEm8IWH5wT3aW8EYvcEmdyufF51Oa9BzewJvAynHIKlrTWrJpwfZ0gFomCDxwUKIx2i4G/5sNDe3o5NgAncIdyf48UM+Bt8hc+giwJp0LWRfBsY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bp.renesas.com; spf=pass smtp.mailfrom=bp.renesas.com; arc=none smtp.client-ip=210.160.252.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=bp.renesas.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bp.renesas.com X-IronPort-AV: E=Sophos;i="6.07,202,1708354800"; d="scan'208";a="201479155" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie5.idc.renesas.com with ESMTP; 15 Apr 2024 18:48:43 +0900 Received: from renesas-deb12.cephei.uk (unknown [10.226.93.74]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id 0A3EC4006DE8; Mon, 15 Apr 2024 18:48:39 +0900 (JST) From: Paul Barker To: Sergey Shtylyov , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Paul Barker , =?utf-8?q?Niklas_S=C3=B6der?= =?utf-8?q?lund?= , Geert Uytterhoeven , netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [net-next RFC v3 6/7] net: ravb: Use NAPI threaded mode on 1-core CPUs with GbEth IP Date: Mon, 15 Apr 2024 10:48:03 +0100 Message-Id: <20240415094804.8016-7-paul.barker.ct@bp.renesas.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240415094804.8016-1-paul.barker.ct@bp.renesas.com> References: <20240415094804.8016-1-paul.barker.ct@bp.renesas.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC NAPI Threaded mode (along with the previously enabled SW IRQ Coalescing) is required to improve network stack performance for single core SoCs using the GbEth IP (currently the RZ/G2L SoC family and the RZ/G3S SoC). This patch gives the following improvements during testing with iperf3. * RZ/G2UL: * TCP TX: +32% bandwidth (638Mbps -> 841Mbps) * TXP RX: +8.8% bandwidth (667Mbps -> 726Mbps) * UDP RX: +104% bandwidth (53Mbps -> 108Mbps) * RZ/G3S: * TCP TX: 29% bandwidth (529Mbps -> 681Mbps) * UDP RX: +1290% bandwidth (6.46Mbps -> 90Mbps) * RZ/Five: * UDP RX: Test no longer crashes (0 -> 20 Mbps) This patch gives the following reductions in performance in the same testing: * RZ/G2UL: * UDP TX: -7.5% bandwidth (594Mbps -> 549Mbps) * RZ/G3S: * UDP TX: -5% bandwidth (625Mbps -> 594Mbps) These losses are considered acceptable given the benefits shown above. If UDP TX bandwidth must be maximised for a particular use case, NAPI threaded mode can be disabled at runtime via sysfs writes. The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL & RZ/G3S) is particularly critical. Signed-off-by: Paul Barker Reviewed-by: Sergey Shtylyov --- drivers/net/ethernet/renesas/ravb_main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index 26b70b996bd3..7434faf0820c 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -2938,8 +2938,11 @@ static int ravb_probe(struct platform_device *pdev) if (info->nc_queues) netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll); - if (info->needs_irq_coalesce) + if (info->needs_irq_coalesce) { netdev_sw_irq_coalesce_default_on(ndev); + if (num_present_cpus() == 1) + dev_set_threaded(ndev, true); + } /* Network device register */ error = register_netdev(ndev);