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From: Jesper Dangaard Brouer <jbrouer@redhat.com>
To: Stanislav Fomichev <sdf@google.com>, bpf@vger.kernel.org
Cc: brouer@redhat.com, ast@kernel.org, daniel@iogearbox.net,
	andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
	yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org,
	haoluo@google.com, jolsa@kernel.org, kuba@kernel.org,
	toke@kernel.org, willemb@google.com, dsahern@kernel.org,
	magnus.karlsson@intel.com, bjorn@kernel.org,
	maciej.fijalkowski@intel.com, hawk@kernel.org,
	netdev@vger.kernel.org, xdp-hints@xdp-project.net,
	Saeed Mahameed <saeedm@nvidia.com>
Subject: [xdp-hints] Re: [PATCH bpf-next 0/9] xsk: TX metadata
Date: Wed, 9 Aug 2023 22:09:10 +0200	[thread overview]
Message-ID: <0cd7fa8a-6fe6-9945-4656-b4bd941b3d3c@redhat.com> (raw)
In-Reply-To: <20230809165418.2831456-1-sdf@google.com>



On 09/08/2023 18.54, Stanislav Fomichev wrote:
> This series implements initial TX metadata (offloads) for AF_XDP.
> See patch #2 for the main implementation and mlx5-one for the
> example on how to consume the metadata on the device side.
> 
> Starting with two types of offloads:
> - request TX timestamp (and write it back into the metadata area)
> - request TX checksum offload
> 
> Changes since last RFC:
> - add /* private: */ comments to headers (Simon)
> - handle metadata only in the first frag (Simon)
> - rename xdp_hw_metadata flags (Willem)
> - s/tmo_request_checksum/tmo_request_timestamp/ in xdp_metadata_ops
>    comment (Willem)
> - Documentation/networking/xsk-tx-metadata.rst
> 
> RFC v4: https://lore.kernel.org/bpf/20230724235957.1953861-1-sdf@google.com/
> 
> Performance:
> 
> I've implemented a small xskgen tool to try to saturate single tx queue:
> https://github.com/fomichev/xskgen/tree/master
> 
> Here are the performance numbers with some analysis.
> 

What is the clock freq GHz for the CPU used for this benchmark?

> 1. Baseline. Running with commit eb62e6aef940 ("Merge branch 'bpf:
> Support bpf_get_func_ip helper in uprobes'"), nothing from this series:
> 
> - with 1400 bytes of payload: 98 gbps, 8 mpps
> ./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189130 sec, 98.357623 gbps 8.409509 mpps
> 
> - with 200 bytes of payload: 49 gbps, 23 mpps
> ./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000064 packets 20960134144 bits, took 0.422235 sec, 49.640921 gbps 23.683645 mpps
> 
> 2. Adding single commit that supports reserving XDP_TX_METADATA_LEN
>     changes nothing numbers-wise.
> 
> - baseline for 1400
> ./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189247 sec, 98.347946 gbps 8.408682 mpps
> 
> - baseline for 200
> ./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 20960000000 bits, took 0.421248 sec, 49.756913 gbps 23.738985 mpps
> 
> 3. Adding -M flag causes xskgen to reserve the metadata and fill it, but
>     doesn't set XDP_TX_METADATA descriptor option.
> 
> - new baseline for 1400 (with only filling the metadata)
> ./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.188767 sec, 98.387657 gbps 8.412077 mpps
> 
> - new baseline for 200 (with only filling the metadata)
> ./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 20960000000 bits, took 0.410213 sec, 51.095407 gbps 24.377579 mpps
> (the numbers go sligtly up here, not really sure why, maybe some cache-related
> side-effects?
> 

Notice this change/improvement (23.7 to 24.4 Mpps) is only 1 nanosec.
  - (1/24.377579-1/23.738985)*10^3 = -1.103499 nanosec

This 1 nanosec could be noise in your testlab.


> 4. Next, I'm running the same test but with the commit that adds actual
>     general infra to parse XDP_TX_METADATA (but no driver support).
>     Essentially applying "xsk: add TX timestamp and TX checksum offload support"
>     from this series. Numbers are the same.
> 
> - fill metadata for 1400
> ./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.188430 sec, 98.415557 gbps 8.414463 mpps
> 
> - fill metadata for 200
> ./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 20960000000 bits, took 0.411559 sec, 50.928299 gbps 24.297853 mpps
> 
> - request metadata for 1400
> ./xskgen -m -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.188723 sec, 98.391299 gbps 8.412389 mpps
> 
> - request metadata for 200
> ./xskgen -m -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000064 packets 20960134144 bits, took 0.411240 sec, 50.968131 gbps 24.316856 mpps
> 
> 5. Now, for the most interesting part, I'm adding mlx5 driver support.
>     The mpps for 200 bytes case goes down from 23 mpps to 19 mpps, but
>     _only_ when I enable the metadata. This looks like a side effect
>     of me pushing extra metadata pointer via mlx5e_xdpi_fifo_push.
>     Hence, this part is wrapped into 'if (xp_tx_metadata_enabled)'
>     to not affect the existing non-metadata use-cases. Since this is not
>     regressing existing workloads, I'm not spending any time trying to
>     optimize it more (and leaving it up to mlx owners to purse if
>     they see any good way to do it).
> 
> - same baseline
> ./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189434 sec, 98.332484 gbps 8.407360 mpps
> 
> ./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000128 packets 20960268288 bits, took 0.425254 sec, 49.288821 gbps 23.515659 mpps
> 
> - fill metadata for 1400
> ./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189528 sec, 98.324714 gbps 8.406696 mpps
> 
> - fill metadata for 200
> ./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000128 packets 20960268288 bits, took 0.519085 sec, 40.379260 gbps 19.264914 mpps
> 

This change from 23 mpps to 19 mpps is approx 10 nanosec
  - (1/23.738985-1/19.264914)*10^3 = -9.78 nanosec
  - (1/23.515659-1/19.264914)*10^3 = -9.38 nanosec

A 10 nanosec difference is more than noise.


> - request metadata for 1400
> ./xskgen -m -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189329 sec, 98.341165 gbps 8.408102 mpps
> 
> - request metadata for 200
> ./xskgen -m -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000128 packets 20960268288 bits, took 0.519929 sec, 40.313713 gbps 19.233642 mpps
> 
> Cc: Saeed Mahameed <saeedm@nvidia.com>
> 
> Stanislav Fomichev (9):
>    xsk: Support XDP_TX_METADATA_LEN
>    xsk: add TX timestamp and TX checksum offload support
>    tools: ynl: print xsk-features from the sample
>    net/mlx5e: Implement AF_XDP TX timestamp and checksum offload
>    selftests/xsk: Support XDP_TX_METADATA_LEN
>    selftests/bpf: Add csum helpers
>    selftests/bpf: Add TX side to xdp_metadata
>    selftests/bpf: Add TX side to xdp_hw_metadata
>    xsk: document XDP_TX_METADATA_LEN layout
> 
>   Documentation/netlink/specs/netdev.yaml       |  20 ++
>   Documentation/networking/index.rst            |   1 +
>   Documentation/networking/xsk-tx-metadata.rst  |  75 +++++++
>   drivers/net/ethernet/mellanox/mlx5/core/en.h  |   4 +-
>   .../net/ethernet/mellanox/mlx5/core/en/xdp.c  |  72 ++++++-
>   .../net/ethernet/mellanox/mlx5/core/en/xdp.h  |  10 +-
>   .../ethernet/mellanox/mlx5/core/en/xsk/tx.c   |  11 +-
>   .../net/ethernet/mellanox/mlx5/core/en_main.c |   1 +
>   include/linux/netdevice.h                     |  27 +++
>   include/linux/skbuff.h                        |   5 +-
>   include/net/xdp_sock.h                        |  61 ++++++
>   include/net/xdp_sock_drv.h                    |  13 ++
>   include/net/xsk_buff_pool.h                   |   6 +
>   include/uapi/linux/if_xdp.h                   |  36 ++++
>   include/uapi/linux/netdev.h                   |  16 ++
>   net/core/netdev-genl.c                        |  12 +-
>   net/xdp/xsk.c                                 |  61 ++++++
>   net/xdp/xsk_buff_pool.c                       |   1 +
>   net/xdp/xsk_queue.h                           |  19 +-
>   tools/include/uapi/linux/if_xdp.h             |  50 ++++-
>   tools/include/uapi/linux/netdev.h             |  15 ++
>   tools/net/ynl/generated/netdev-user.c         |  19 ++
>   tools/net/ynl/generated/netdev-user.h         |   3 +
>   tools/net/ynl/samples/netdev.c                |   6 +
>   tools/testing/selftests/bpf/network_helpers.h |  43 ++++
>   .../selftests/bpf/prog_tests/xdp_metadata.c   |  31 ++-
>   tools/testing/selftests/bpf/xdp_hw_metadata.c | 201 +++++++++++++++++-
>   tools/testing/selftests/bpf/xsk.c             |  17 ++
>   tools/testing/selftests/bpf/xsk.h             |   1 +
>   29 files changed, 793 insertions(+), 44 deletions(-)
>   create mode 100644 Documentation/networking/xsk-tx-metadata.rst
> 

Thanks for working on this :-)
--Jesper


  parent reply	other threads:[~2023-08-09 20:09 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-09 16:54 [xdp-hints] " Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 1/9] xsk: Support XDP_TX_METADATA_LEN Stanislav Fomichev
2023-08-14 10:56   ` [xdp-hints] " Maciej Fijalkowski
2023-08-14 18:05     ` Stanislav Fomichev
2023-08-14 22:24       ` Stanislav Fomichev
2023-08-15 12:19         ` Magnus Karlsson
2023-08-15 18:21           ` Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 2/9] xsk: add TX timestamp and TX checksum offload support Stanislav Fomichev
2023-08-09 20:18   ` [xdp-hints] " Jesper Dangaard Brouer
2023-08-10 18:25     ` Stanislav Fomichev
2023-08-10  5:26   ` kernel test robot
2023-08-10  6:12   ` kernel test robot
2023-08-14 11:01   ` Maciej Fijalkowski
2023-08-14 18:05     ` Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 3/9] tools: ynl: print xsk-features from the sample Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 4/9] net/mlx5e: Implement AF_XDP TX timestamp and checksum offload Stanislav Fomichev
2023-08-14 11:02   ` [xdp-hints] " Maciej Fijalkowski
2023-08-14 18:05     ` Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 5/9] selftests/xsk: Support XDP_TX_METADATA_LEN Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 6/9] selftests/bpf: Add csum helpers Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 7/9] selftests/bpf: Add TX side to xdp_metadata Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 8/9] selftests/bpf: Add TX side to xdp_hw_metadata Stanislav Fomichev
2023-08-09 16:54 ` [xdp-hints] [PATCH bpf-next 9/9] xsk: document XDP_TX_METADATA_LEN layout Stanislav Fomichev
2023-08-09 20:39   ` [xdp-hints] " Jesper Dangaard Brouer
2023-08-10 18:17     ` Stanislav Fomichev
2023-08-09 20:09 ` Jesper Dangaard Brouer [this message]
2023-08-10 18:23   ` [xdp-hints] Re: [PATCH bpf-next 0/9] xsk: TX metadata Stanislav Fomichev
2023-08-14 11:13 ` Maciej Fijalkowski
2023-08-14 18:04   ` Stanislav Fomichev

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