netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: David Ahern <dsahern@gmail.com>
To: Boris Pismenny <borisp@mellanox.com>,
	kuba@kernel.org, davem@davemloft.net, saeedm@nvidia.com,
	hch@lst.de, sagi@grimberg.me, axboe@fb.com, kbusch@kernel.org,
	viro@zeniv.linux.org.uk, edumazet@google.com
Cc: boris.pismenny@gmail.com, linux-nvme@lists.infradead.org,
	netdev@vger.kernel.org, benishay@nvidia.com, ogerlitz@nvidia.com,
	yorayz@nvidia.com, Ben Ben-Ishay <benishay@mellanox.com>,
	Or Gerlitz <ogerlitz@mellanox.com>,
	Yoray Zack <yorayz@mellanox.com>
Subject: Re: [PATCH v1 net-next 02/15] net: Introduce direct data placement tcp offload
Date: Mon, 7 Dec 2020 17:42:14 -0700	[thread overview]
Message-ID: <6f48fa5d-465c-5c38-ea45-704e86ba808b@gmail.com> (raw)
In-Reply-To: <20201207210649.19194-3-borisp@mellanox.com>

On 12/7/20 2:06 PM, Boris Pismenny wrote:
> This commit introduces direct data placement offload for TCP.
> This capability is accompanied by new net_device operations that
> configure
> hardware contexts. There is a context per socket, and a context per DDP
> opreation. Additionally, a resynchronization routine is used to assist
> hardware handle TCP OOO, and continue the offload.
> Furthermore, we let the offloading driver advertise what is the max hw
> sectors/segments.
> 
> Using this interface, the NIC hardware will scatter TCP payload directly
> to the BIO pages according to the command_id.
> To maintain the correctness of the network stack, the driver is expected
> to construct SKBs that point to the BIO pages.
> 
> This, the SKB represents the data on the wire, while it is pointing
> to data that is already placed in the destination buffer.
> As a result, data from page frags should not be copied out to
> the linear part.
> 
> As SKBs that use DDP are already very memory efficient, we modify
> skb_condence to avoid copying data from fragments to the linear
> part of SKBs that belong to a socket that uses DDP offload.
> 
> A follow-up patch will use this interface for DDP in NVMe-TCP.
> 

You call this Direct Data Placement - which sounds like a marketing name.

Fundamentally, this starts with offloading TCP socket buffers for a
specific flow, so generically a TCP Rx zerocopy for kernel stack managed
sockets (as opposed to AF_XDP's zerocopy). Why is this not building in
that level of infrastructure first and adding ULPs like NVME on top?

  reply	other threads:[~2020-12-08  0:43 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-07 21:06 [PATCH v1 net-next 00/15] nvme-tcp receive offloads Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 01/15] iov_iter: Skip copy in memcpy_to_page if src==dst Boris Pismenny
2020-12-08  0:39   ` David Ahern
2020-12-08 14:30     ` Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 02/15] net: Introduce direct data placement tcp offload Boris Pismenny
2020-12-08  0:42   ` David Ahern [this message]
2020-12-08 14:36     ` Boris Pismenny
2020-12-09  0:38       ` David Ahern
2020-12-09  8:15         ` Boris Pismenny
2020-12-10  4:26           ` David Ahern
2020-12-11  2:01             ` Jakub Kicinski
2020-12-11  2:43               ` David Ahern
2020-12-11 18:45                 ` Jakub Kicinski
2020-12-11 18:58                   ` Eric Dumazet
2020-12-11 19:59                   ` David Ahern
2020-12-11 23:05                     ` Jonathan Lemon
2020-12-13 18:34                   ` Boris Pismenny
2020-12-13 18:21             ` Boris Pismenny
2020-12-15  5:19               ` David Ahern
2020-12-17 19:06                 ` Boris Pismenny
2020-12-18  0:44                   ` David Ahern
2020-12-09  0:57   ` David Ahern
2020-12-09  1:11     ` David Ahern
2020-12-09  8:28       ` Boris Pismenny
2020-12-09  8:25     ` Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 03/15] net: Introduce crc offload for tcp ddp ulp Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 04/15] net/tls: expose get_netdev_for_sock Boris Pismenny
2020-12-09  1:06   ` David Ahern
2020-12-09  7:41     ` Boris Pismenny
2020-12-10  3:39       ` David Ahern
2020-12-11 18:43         ` Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 05/15] nvme-tcp: Add DDP offload control path Boris Pismenny
2020-12-10 17:15   ` Shai Malin
2020-12-14  6:38     ` Boris Pismenny
2020-12-15 13:33       ` Shai Malin
2020-12-17 18:51         ` Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 06/15] nvme-tcp: Add DDP data-path Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 07/15] nvme-tcp : Recalculate crc in the end of the capsule Boris Pismenny
2020-12-15 14:07   ` Shai Malin
2020-12-07 21:06 ` [PATCH v1 net-next 08/15] nvme-tcp: Deal with netdevice DOWN events Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 09/15] net/mlx5: Header file changes for nvme-tcp offload Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 10/15] net/mlx5: Add 128B CQE for NVMEoTCP offload Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 11/15] net/mlx5e: TCP flow steering for nvme-tcp Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 12/15] net/mlx5e: NVMEoTCP DDP offload control path Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 13/15] net/mlx5e: NVMEoTCP, data-path for DDP offload Boris Pismenny
2020-12-18  0:57   ` David Ahern
2020-12-07 21:06 ` [PATCH v1 net-next 14/15] net/mlx5e: NVMEoTCP statistics Boris Pismenny
2020-12-07 21:06 ` [PATCH v1 net-next 15/15] net/mlx5e: NVMEoTCP workaround CRC after resync Boris Pismenny
2021-01-14  1:27 ` [PATCH v1 net-next 00/15] nvme-tcp receive offloads Sagi Grimberg
2021-01-14  4:47   ` David Ahern
2021-01-14 19:21     ` Boris Pismenny
2021-01-14 19:17   ` Boris Pismenny
2021-01-14 21:07     ` Sagi Grimberg

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=6f48fa5d-465c-5c38-ea45-704e86ba808b@gmail.com \
    --to=dsahern@gmail.com \
    --cc=axboe@fb.com \
    --cc=benishay@mellanox.com \
    --cc=benishay@nvidia.com \
    --cc=boris.pismenny@gmail.com \
    --cc=borisp@mellanox.com \
    --cc=davem@davemloft.net \
    --cc=edumazet@google.com \
    --cc=hch@lst.de \
    --cc=kbusch@kernel.org \
    --cc=kuba@kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=netdev@vger.kernel.org \
    --cc=ogerlitz@mellanox.com \
    --cc=ogerlitz@nvidia.com \
    --cc=saeedm@nvidia.com \
    --cc=sagi@grimberg.me \
    --cc=viro@zeniv.linux.org.uk \
    --cc=yorayz@mellanox.com \
    --cc=yorayz@nvidia.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).