From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Alex G." Subject: Re: [PATCH v6 8/9] net/mlx5: Do not call pcie_print_link_status() Date: Wed, 8 Aug 2018 11:33:51 -0500 Message-ID: <79264a38-e3e4-d270-95df-a09047f7a15e@gmail.com> References: <20180806232600.25694-1-mr.nuke.me@gmail.com> <20180806232600.25694-8-mr.nuke.me@gmail.com> <20180808060848.GQ13378@mtr-leonro.mtl.com> <05056a70-ee78-ea3c-0b9b-6d64a8663b11@mellanox.com> <20180808154142.GZ13378@mtr-leonro.mtl.com> <5578cd9a-e4f0-85ab-4a86-bfa23eec136c@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, jakub.kicinski@netronome.com, keith.busch@intel.com, alex_gagniuc@dellteam.com, austin_bolen@dell.com, shyam_iyer@dell.com, Ariel Elior , everest-linux-l2@cavium.com, "David S. Miller" , Michael Chan , Ganesh Goudar , Jeff Kirsher , Tariq Toukan , Saeed Mahameed , Dirk van der Merwe , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-rdma@vger.kernel.org, oss-drivers@netronome.com To: Tal Gilboa , Leon Romanovsky Return-path: In-Reply-To: <5578cd9a-e4f0-85ab-4a86-bfa23eec136c@mellanox.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 08/08/2018 10:56 AM, Tal Gilboa wrote: > On 8/8/2018 6:41 PM, Leon Romanovsky wrote: >> On Wed, Aug 08, 2018 at 05:23:12PM +0300, Tal Gilboa wrote: >>> On 8/8/2018 9:08 AM, Leon Romanovsky wrote: >>>> On Mon, Aug 06, 2018 at 06:25:42PM -0500, Alexandru Gagniuc wrote: >>>>> This is now done by the PCI core to warn of sub-optimal bandwidth. >>>>> >>>>> Signed-off-by: Alexandru Gagniuc >>>>> --- >>>>>    drivers/net/ethernet/mellanox/mlx5/core/main.c | 4 ---- >>>>>    1 file changed, 4 deletions(-) >>>>> >>>> >>>> Thanks, >>>> Reviewed-by: Leon Romanovsky >>>> >>> >>> Alex, >>> I loaded mlx5 driver with and without these series. The report in >>> dmesg is >>> now missing. From what I understood, the status should be reported at >>> least >>> once, even if everything is in order. >> >> It is not what this series is doing and it removes prints completely if >> fabric can deliver more than card is capable. >> >>> We need this functionality to stay. >> >> I'm not sure that you need this information in driver's dmesg output, >> but most probably something globally visible and accessible per-pci >> device. > > Currently we have users that look for it. If we remove the dmesg print > we need this to be reported elsewhere. Adding it to sysfs for example > should be a valid solution for our case. I think a stop-gap measure is to leave the pcie_print_link_status() call in drivers that really need it for whatever reason. Implementing a reliable reporting through sysfs might take some tinkering, and I don't think it's a sufficient reason to block the heart of this series -- being able to detect bottlenecks and link downtraining. Alex >> >>> >>> net-next (dmesg output for 07:00.0): >>> [270498.625351] mlx5_core 0000:07:00.0: firmware version: 14.22.4020 >>> [270498.632130] mlx5_core 0000:07:00.0: 63.008 Gb/s available PCIe >>> bandwidth >>> (8 GT/s x8 link) >>> [270499.169533] (0000:07:00.0): E-Switch: Total vports 9, per vport: max >>> uc(1024) max mc(16384) >>> [270499.182358] mlx5_core 0000:07:00.0: Port module event: module 0, >>> Cable >>> plugged >>> >>> net-next + patches (dmesg output for 07:00.0): >>> [  331.608472] mlx5_core 0000:07:00.0: firmware version: 14.22.4020 >>> [  332.564938] (0000:07:00.0): E-Switch: Total vports 9, per vport: max >>> uc(1024) max mc(16384) >>> [  332.616271] mlx5_core 0000:07:00.0: Port module event: module 0, >>> Cable >>> plugged >>> >>>