From patchwork Thu May 3 20:00:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 908225 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="1se8pP3H"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40cQxV0252z9s4s for ; Fri, 4 May 2018 06:00:46 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751522AbeECUAm (ORCPT ); Thu, 3 May 2018 16:00:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:34178 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750823AbeECUAj (ORCPT ); Thu, 3 May 2018 16:00:39 -0400 Received: from localhost (unknown [69.71.5.252]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 92C122176D; Thu, 3 May 2018 20:00:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1525377638; bh=qBVMNACNhTkJajFGgLbb49GA1jxO76CFZaLYSbH8qY4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=1se8pP3Hvu1t1gjPg6ToJxTpKaImey3q6spR+583N3fgMxDu5jIeH8GJ0VAGsbDpc 0CV3CthM3k0cB98Moni0mifayHmUzG4/eG4fkZ9fCkk3vQvggPLXFJ0bOtYeEeQdKC 2296zfT1650wEy29CknRQTc7siMbhJiJGKDY/n3M= Subject: [PATCH v6 4/5] ixgbe: Report PCIe link properties with pcie_print_link_status() From: Bjorn Helgaas To: Jeff Kirsher , Ganesh Goudar , Michael Chan , Ariel Elior Cc: linux-pci@vger.kernel.org, everest-linux-l2@cavium.com, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Tal Gilboa , Tariq Toukan , Jacob Keller , Jakub Kicinski Date: Thu, 03 May 2018 15:00:36 -0500 Message-ID: <152537763602.62474.15659483976051204438.stgit@bhelgaas-glaptop.roam.corp.google.com> In-Reply-To: <152537719056.62474.2571390812509425478.stgit@bhelgaas-glaptop.roam.corp.google.com> References: <152537719056.62474.2571390812509425478.stgit@bhelgaas-glaptop.roam.corp.google.com> User-Agent: StGit/0.18 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Bjorn Helgaas Previously the driver used pcie_get_minimum_link() to warn when the NIC is in a slot that can't supply as much bandwidth as the NIC could use. pcie_get_minimum_link() can be misleading because it finds the slowest link and the narrowest link (which may be different links) without considering the total bandwidth of each link. For a path with a 16 GT/s x1 link and a 2.5 GT/s x16 link, it returns 2.5 GT/s x1, which corresponds to 250 MB/s of bandwidth, not the true available bandwidth of about 1969 MB/s for a 16 GT/s x1 link. Use pcie_print_link_status() to report PCIe link speed and possible limitations instead of implementing this in the driver itself. This finds the slowest link in the path to the device by computing the total bandwidth of each link and compares that with the capabilities of the device. The dmesg change is: - PCI Express bandwidth of %dGT/s available - (Speed:%s, Width: x%d, Encoding Loss:%s) + %u.%03u Gb/s available PCIe bandwidth (%s x%d link) or, if the device is capable of better performance than is available in the current slot: - This is not sufficient for optimal performance of this card. - For optimal performance, at least %dGT/s of bandwidth is required. - A slot with more lanes and/or higher speed is suggested. + %u.%03u Gb/s available PCIe bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link) Note that the driver previously used dev_warn() to suggest using a different slot, but pcie_print_link_status() uses dev_info() because if the platform has no faster slot available, the user can't do anything about the warning and may not want to be bothered with it. Signed-off-by: Bjorn Helgaas Acked-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 47 +------------------------ 1 file changed, 1 insertion(+), 46 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index afadba99f7b8..8990285f6e12 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -270,9 +270,6 @@ static void ixgbe_check_minimum_link(struct ixgbe_adapter *adapter, int expected_gts) { struct ixgbe_hw *hw = &adapter->hw; - int max_gts = 0; - enum pci_bus_speed speed = PCI_SPEED_UNKNOWN; - enum pcie_link_width width = PCIE_LNK_WIDTH_UNKNOWN; struct pci_dev *pdev; /* Some devices are not connected over PCIe and thus do not negotiate @@ -288,49 +285,7 @@ static void ixgbe_check_minimum_link(struct ixgbe_adapter *adapter, else pdev = adapter->pdev; - if (pcie_get_minimum_link(pdev, &speed, &width) || - speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN) { - e_dev_warn("Unable to determine PCI Express bandwidth.\n"); - return; - } - - switch (speed) { - case PCIE_SPEED_2_5GT: - /* 8b/10b encoding reduces max throughput by 20% */ - max_gts = 2 * width; - break; - case PCIE_SPEED_5_0GT: - /* 8b/10b encoding reduces max throughput by 20% */ - max_gts = 4 * width; - break; - case PCIE_SPEED_8_0GT: - /* 128b/130b encoding reduces throughput by less than 2% */ - max_gts = 8 * width; - break; - default: - e_dev_warn("Unable to determine PCI Express bandwidth.\n"); - return; - } - - e_dev_info("PCI Express bandwidth of %dGT/s available\n", - max_gts); - e_dev_info("(Speed:%s, Width: x%d, Encoding Loss:%s)\n", - (speed == PCIE_SPEED_8_0GT ? "8.0GT/s" : - speed == PCIE_SPEED_5_0GT ? "5.0GT/s" : - speed == PCIE_SPEED_2_5GT ? "2.5GT/s" : - "Unknown"), - width, - (speed == PCIE_SPEED_2_5GT ? "20%" : - speed == PCIE_SPEED_5_0GT ? "20%" : - speed == PCIE_SPEED_8_0GT ? "<2%" : - "Unknown")); - - if (max_gts < expected_gts) { - e_dev_warn("This is not sufficient for optimal performance of this card.\n"); - e_dev_warn("For optimal performance, at least %dGT/s of bandwidth is required.\n", - expected_gts); - e_dev_warn("A slot with more lanes and/or higher speed is suggested.\n"); - } + pcie_print_link_status(pdev); } static void ixgbe_service_event_schedule(struct ixgbe_adapter *adapter)