From patchwork Mon Aug 21 07:47:02 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sagi Grimberg X-Patchwork-Id: 27679 X-Patchwork-Delegate: ferruh.yigit@amd.com Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [IPv6:::1]) by dpdk.org (Postfix) with ESMTP id 54E5390F3; Mon, 21 Aug 2017 09:47:13 +0200 (CEST) Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) by dpdk.org (Postfix) with ESMTP id A2EBE8CF4 for ; Mon, 21 Aug 2017 09:47:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=dsifLv8n4jpi/tLwumPwhwlQwK8uY0VZwceMuAcxjM0=; b=PZg/8ncovfHAxzslMl6pBLJSd RBVThK8RhhTw90GW1QfDMyE+KCwEOLkPnrVD66JBXwf864Gg16DZz2+z2kqQxeYeP387B0MiIQ2ht GZRt9rGLtMuw/mHK0IS6HNrLqF28iStsYzt8snpfOdPdDLv5AJgoOFZcl6IcrqYrh2UL1lDdeU8W8 7/OyFZL3U73TZj/YubaeXFITsHMY92W9IVBmnitujGU483tNG754V/+dzcXnsxd0cUe5tftx69vnT pKR/XmbfDHD5St/j4Ump7AbxhAQ2DtoKQv38Vqkc85b9p3R4g85fv/Ku91TGgDu30Q6iFjMkE5lzo z5bJsf7zw==; Received: from bzq-82-81-101-184.red.bezeqint.net ([82.81.101.184] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtpsa (Exim 4.87 #1 (Red Hat Linux)) id 1djhQT-0000ZK-P9; Mon, 21 Aug 2017 07:47:10 +0000 From: Sagi Grimberg To: dev@dpdk.org Cc: Nelio Laranjeiro , Adrien Mazarguil , Shahaf Shuler Date: Mon, 21 Aug 2017 10:47:02 +0300 Message-Id: <1503301622-14220-3-git-send-email-sagi@grimberg.me> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503301622-14220-1-git-send-email-sagi@grimberg.me> References: <1503301622-14220-1-git-send-email-sagi@grimberg.me> Subject: [dpdk-dev] [PATCH 2/2] net/mlx5: don't map doorbell register to write combining 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" From: Shahaf Shuler By default, Verbs maps the doorbell register to write combining. Working with write combining is useful for drivers which use blue flame for the doorbell write. Since mlx5 PMD uses only doorbells and write combining mapping requires an extra memory barrier to flush the doorbell after its write, setting the mapping to un-cached by default. Such change is reduces the max and average round trip latency significantly. Reported-by: Alexander Solganik Signed-off-by: Shahaf Shuler Signed-off-by: Yongseok Koh Signed-off-by: Alexander Solganik Signed-off-by: Sagi Grimberg Acked-by: Nelio Laranjeiro --- drivers/net/mlx5/mlx5.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c index b7e5046325c0..4c2a0b9652e3 100644 --- a/drivers/net/mlx5/mlx5.c +++ b/drivers/net/mlx5/mlx5.c @@ -920,6 +920,8 @@ rte_mlx5_pmd_init(void) * using this PMD, which is not supported in forked processes. */ setenv("RDMAV_HUGEPAGES_SAFE", "1", 1); + /* Don't map UAR to WC if BlueFlame is not used.*/ + setenv("MLX5_SHUT_UP_BF", "1", 1); ibv_fork_init(); rte_pci_register(&mlx5_driver); }