Please, don't take directly, conflicts with io_uring.

To have per request buffer notifications each zerocopy io_uring send
request allocates a new ubuf_info. However, as an skb can carry only
one uarg, it may force the stack to create many small skbs hurting
performance in many ways.

The patchset implements notification, i.e. an io_uring's ubuf_info
extension, stacking. It attempts to link ubuf_info's into a list,
allowing to have multiple of them per skb.

liburing/examples/send-zerocopy shows up 6 times performance improvement
for TCP with 4KB bytes per send, and levels it with MSG_ZEROCOPY. Without
the patchset it requires much larger sends to utilise all potential.

bytes  | before | after (Kqps)
1200   | 195    | 1023
4000   | 193    | 1386
8000   | 154    | 1058

The patches are on top of net-next + io_uring-next:

https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2

First two patches based on net-next:

https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2-netonly

v2: convert xen-netback to ubuf_info_ops (patch 1)
    drop two separately merged io_uring patches

Pavel Begunkov (4):
  net: extend ubuf_info callback to ops structure
  net: add callback for setting a ubuf_info to skb
  io_uring/notif: simplify io_notif_flush()
  io_uring/notif: implement notification stacking

 drivers/net/tap.c                   |  2 +-
 drivers/net/tun.c                   |  2 +-
 drivers/net/xen-netback/common.h    |  5 +-
 drivers/net/xen-netback/interface.c |  2 +-
 drivers/net/xen-netback/netback.c   | 11 ++--
 drivers/vhost/net.c                 |  8 ++-
 include/linux/skbuff.h              | 21 +++++---
 io_uring/notif.c                    | 83 +++++++++++++++++++++++++----
 io_uring/notif.h                    | 12 ++---
 net/core/skbuff.c                   | 36 ++++++++-----
 10 files changed, 134 insertions(+), 48 deletions(-)

-- 
2.44.0

On 4/19/24 12:08, Pavel Begunkov wrote:
> Please, don't take directly, conflicts with io_uring.

When everyone is happy with the patches, Jens and Jakub will hopefully
help to merge them. E.g. first staging net/ specific changes [1] and then
handling all conflicts on the io_uring side.

[1] https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2-netonly


> To have per request buffer notifications each zerocopy io_uring send
> request allocates a new ubuf_info. However, as an skb can carry only
> one uarg, it may force the stack to create many small skbs hurting
> performance in many ways.
> 
> The patchset implements notification, i.e. an io_uring's ubuf_info
> extension, stacking. It attempts to link ubuf_info's into a list,
> allowing to have multiple of them per skb.
> 
> liburing/examples/send-zerocopy shows up 6 times performance improvement
> for TCP with 4KB bytes per send, and levels it with MSG_ZEROCOPY. Without
> the patchset it requires much larger sends to utilise all potential.
> 
> bytes  | before | after (Kqps)
> 1200   | 195    | 1023
> 4000   | 193    | 1386
> 8000   | 154    | 1058
> 
> The patches are on top of net-next + io_uring-next:
> 
> https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2
> 
> First two patches based on net-next:
> 
> https://github.com/isilence/linux.git iou-sendzc/notif-stacking-v2-netonly
> 
> v2: convert xen-netback to ubuf_info_ops (patch 1)
>      drop two separately merged io_uring patches
> 
> Pavel Begunkov (4):
>    net: extend ubuf_info callback to ops structure
>    net: add callback for setting a ubuf_info to skb
>    io_uring/notif: simplify io_notif_flush()
>    io_uring/notif: implement notification stacking
> 
>   drivers/net/tap.c                   |  2 +-
>   drivers/net/tun.c                   |  2 +-
>   drivers/net/xen-netback/common.h    |  5 +-
>   drivers/net/xen-netback/interface.c |  2 +-
>   drivers/net/xen-netback/netback.c   | 11 ++--
>   drivers/vhost/net.c                 |  8 ++-
>   include/linux/skbuff.h              | 21 +++++---
>   io_uring/notif.c                    | 83 +++++++++++++++++++++++++----
>   io_uring/notif.h                    | 12 ++---
>   net/core/skbuff.c                   | 36 ++++++++-----
>   10 files changed, 134 insertions(+), 48 deletions(-)
> 

-- 
Pavel Begunkov

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 19 Apr 2024 12:08:38 +0100 you wrote:
> Please, don't take directly, conflicts with io_uring.
> 
> To have per request buffer notifications each zerocopy io_uring send
> request allocates a new ubuf_info. However, as an skb can carry only
> one uarg, it may force the stack to create many small skbs hurting
> performance in many ways.
> 
> [...]

Here is the summary with links:
  - [io_uring-next/net-next,v2,1/4] net: extend ubuf_info callback to ops structure
    https://git.kernel.org/netdev/net-next/c/7ab4f16f9e24
  - [io_uring-next/net-next,v2,2/4] net: add callback for setting a ubuf_info to skb
    https://git.kernel.org/netdev/net-next/c/65bada80dec1
  - [io_uring-next/net-next,v2,3/4] io_uring/notif: simplify io_notif_flush()
    (no matching commit)
  - [io_uring-next/net-next,v2,4/4] io_uring/notif: implement notification stacking
    (no matching commit)

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

On Fri, 19 Apr 2024 12:08:38 +0100, Pavel Begunkov wrote:
> Please, don't take directly, conflicts with io_uring.
> 
> To have per request buffer notifications each zerocopy io_uring send
> request allocates a new ubuf_info. However, as an skb can carry only
> one uarg, it may force the stack to create many small skbs hurting
> performance in many ways.
> 
> [...]

Applied, thanks!

[3/4] io_uring/notif: simplify io_notif_flush()
      commit: 5a569469b973cb7a6c58192a37dfb8418686e518
[4/4] io_uring/notif: implement notification stacking
      commit: 6fe4220912d19152a26ce19713ab232f4263018d

Best regards,
-- 
Jens Axboe