Re: [PATCH v6 8/9] net/mlx5: Do not call pcie_print_link_status()

From: Tal Gilboa <talgi@mellanox.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Alexandru Gagniuc <mr.nuke.me@gmail.com>,
	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 <ariel.elior@cavium.com>,
	everest-linux-l2@cavium.com,
	"David S. Miller" <davem@davemloft.net>,
	Michael Chan <michael.chan@broadcom.com>,
	Ganesh Goudar <ganeshgr@chelsio.com>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	Tariq Toukan <tariqt@mellanox.com>,
	Saeed Mahameed <saeedm@mellanox.com>,
	Dirk van der Merwe <dirk.vandermerwe@netronome.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	intel-wired-lan@lists.osuosl.org, linux-rdma@vger.kernel.org,
	oss-drivers@netronome.com
Subject: Re: [PATCH v6 8/9] net/mlx5: Do not call pcie_print_link_status()
Date: Wed, 8 Aug 2018 18:56:29 +0300	[thread overview]
Message-ID: <5578cd9a-e4f0-85ab-4a86-bfa23eec136c@mellanox.com> (raw)
In-Reply-To: <20180808154142.GZ13378@mtr-leonro.mtl.com>

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 <mr.nuke.me@gmail.com>
>>>> ---
>>>>    drivers/net/ethernet/mellanox/mlx5/core/main.c | 4 ----
>>>>    1 file changed, 4 deletions(-)
>>>>
>>>
>>> Thanks,
>>> Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
>>>
>>
>> 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.

> 
>>
>> 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
>>
>>