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From: Parav Pandit <parav@nvidia.com>
To: Parav Pandit <parav@nvidia.com>,
	Alexander Duyck <alexander.duyck@gmail.com>,
	David Ahern <dsahern@gmail.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
	Saeed Mahameed <saeed@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Leon Romanovsky <leonro@nvidia.com>,
	Netdev <netdev@vger.kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	David Ahern <dsahern@kernel.org>,
	Jacob Keller <jacob.e.keller@intel.com>,
	"Sridhar Samudrala" <sridhar.samudrala@intel.com>,
	"Ertman, David M" <david.m.ertman@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	"Kiran Patil" <kiran.patil@intel.com>,
	Greg KH <gregkh@linuxfoundation.org>
Subject: RE: [net-next v4 00/15] Add mlx5 subfunction support
Date: Fri, 18 Dec 2020 05:36:48 +0000	[thread overview]
Message-ID: <BY5PR12MB4322E1121673E1DDB0C5B2C4DCC30@BY5PR12MB4322.namprd12.prod.outlook.com> (raw)
In-Reply-To: <BY5PR12MB43220950B3A93B9E548976C7DCC30@BY5PR12MB4322.namprd12.prod.outlook.com>



> From: Parav Pandit <parav@nvidia.com>
> Sent: Friday, December 18, 2020 10:51 AM
> 
> > From: Alexander Duyck <alexander.duyck@gmail.com>
> > Sent: Friday, December 18, 2020 8:41 AM
> >
> > On Thu, Dec 17, 2020 at 5:30 PM David Ahern <dsahern@gmail.com> wrote:
> > >
> > > On 12/16/20 3:53 PM, Alexander Duyck wrote:
> > The problem is PCIe DMA wasn't designed to function as a network
> > switch fabric and when we start talking about a 400Gb NIC trying to
> > handle over 256 subfunctions it will quickly reduce the
> > receive/transmit throughput to gigabit or less speeds when encountering
> hardware multicast/broadcast replication.
> > With 256 subfunctions a simple 60B ARP could consume more than 19KB of
> > PCIe bandwidth due to the packet having to be duplicated so many
> > times. In my mind it should be simpler to simply clone a single skb
> > 256 times, forward that to the switchdev ports, and have them perform
> > a bypass (if available) to deliver it to the subfunctions. That's why
> > I was thinking it might be a good time to look at addressing it.
> Linux tc framework is rich to address this and already used by openvswich for
> years now.
> Today arp broadcasts are not offloaded. They go through software patch and
s/patch/path

> replicated in the L2 domain.
> It is a solved problem for many years now.

  reply	other threads:[~2020-12-18  5:37 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-14 21:43 [net-next v4 00/15] Add mlx5 subfunction support Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 01/15] net/mlx5: Fix compilation warning for 32-bit platform Saeed Mahameed
2020-12-14 22:31   ` Alexander Duyck
2020-12-14 22:45     ` Saeed Mahameed
2020-12-15  4:59     ` Leon Romanovsky
2020-12-14 21:43 ` [net-next v4 02/15] devlink: Prepare code to fill multiple port function attributes Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 03/15] devlink: Introduce PCI SF port flavour and port attribute Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 04/15] devlink: Support add and delete devlink port Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 05/15] devlink: Support get and set state of port function Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 06/15] net/mlx5: Introduce vhca state event notifier Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 07/15] net/mlx5: SF, Add auxiliary device support Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 08/15] net/mlx5: SF, Add auxiliary device driver Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 09/15] net/mlx5: E-switch, Prepare eswitch to handle SF vport Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 10/15] net/mlx5: E-switch, Add eswitch helpers for " Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 11/15] net/mlx5: SF, Add port add delete functionality Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 12/15] net/mlx5: SF, Port function state change support Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 13/15] devlink: Add devlink port documentation Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 14/15] devlink: Extend devlink port documentation for subfunctions Saeed Mahameed
2020-12-14 21:43 ` [net-next v4 15/15] net/mlx5: Add devlink subfunction port documentation Saeed Mahameed
2020-12-15  1:53 ` [net-next v4 00/15] Add mlx5 subfunction support Alexander Duyck
2020-12-15  2:44   ` David Ahern
2020-12-15 16:16     ` Alexander Duyck
2020-12-15 16:59       ` Parav Pandit
2020-12-15  5:48   ` Parav Pandit
2020-12-15 18:47     ` Alexander Duyck
2020-12-15 20:05       ` Saeed Mahameed
2020-12-15 21:03       ` Jason Gunthorpe
2020-12-16  1:12       ` Edwin Peer
2020-12-16  2:39         ` Jason Gunthorpe
2020-12-16  3:12         ` Alexander Duyck
2020-12-15 20:59     ` David Ahern
2020-12-15  6:15   ` Saeed Mahameed
2020-12-15 19:12     ` Alexander Duyck
2020-12-15 20:35       ` Saeed Mahameed
2020-12-15 21:28         ` Jakub Kicinski
2020-12-16  6:50           ` Leon Romanovsky
2020-12-16 17:59             ` Saeed Mahameed
2020-12-15 21:41         ` Alexander Duyck
2020-12-16  0:19           ` Jason Gunthorpe
2020-12-16  2:19             ` Alexander Duyck
2020-12-16  3:03               ` Jason Gunthorpe
2020-12-16  4:13                 ` Alexander Duyck
2020-12-16  4:45                   ` Parav Pandit
2020-12-16 13:33                   ` Jason Gunthorpe
2020-12-16 16:31                     ` Alexander Duyck
2020-12-16 17:51                       ` Jason Gunthorpe
2020-12-16 19:27                         ` Alexander Duyck
2020-12-16 20:35                           ` Jason Gunthorpe
2020-12-16 22:53                             ` Alexander Duyck
2020-12-17  0:38                               ` Jason Gunthorpe
2020-12-17 18:48                                 ` Alexander Duyck
2020-12-17 19:40                                   ` Jason Gunthorpe
2020-12-17 21:05                                     ` Alexander Duyck
2020-12-18  0:08                                       ` Jason Gunthorpe
2020-12-18  1:30                               ` David Ahern
2020-12-18  3:11                                 ` Alexander Duyck
2020-12-18  3:55                                   ` David Ahern
2020-12-18 15:54                                     ` Alexander Duyck
2020-12-18  5:20                                   ` Parav Pandit
2020-12-18  5:36                                     ` Parav Pandit [this message]
2020-12-18 16:01                                     ` Alexander Duyck
2020-12-18 18:01                                       ` Parav Pandit
2020-12-18 19:22                                         ` Alexander Duyck
2020-12-18 20:18                                           ` Jason Gunthorpe
2020-12-19  0:03                                             ` Alexander Duyck

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