From: Jakub Kicinski <kuba@kernel.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Stanislav Fomichev <sdf@google.com>,
bpf@vger.kernel.org, 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, 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
Subject: [xdp-hints] Re: [RFC bpf-next v3 09/14] net/mlx5e: Implement devtx kfuncs
Date: Tue, 11 Jul 2023 17:32:26 -0700 [thread overview]
Message-ID: <20230711173226.7e9cca4a@kernel.org> (raw)
In-Reply-To: <20230711225657.kuvkil776fajonl5@MacBook-Pro-8.local>
On Tue, 11 Jul 2023 15:56:57 -0700 Alexei Starovoitov wrote:
> I think this proves my point: csum is not generalizable even across veth and mlx5.
> Above is a square peg that tries to fit csum_start/offset api (that makes sense from SW pov)
> into HW that has different ideas about csum-ing.
>
> Here is what mlx5 does:
> mlx5e_txwqe_build_eseg_csum(struct mlx5e_txqsq *sq, struct sk_buff *skb,
> struct mlx5e_accel_tx_state *accel,
> struct mlx5_wqe_eth_seg *eseg)
> {
> if (unlikely(mlx5e_ipsec_txwqe_build_eseg_csum(sq, skb, eseg)))
> return;
>
> if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
> eseg->cs_flags = MLX5_ETH_WQE_L3_CSUM;
> if (skb->encapsulation) {
This should be irrelevant today, as LCO exists?
> eseg->cs_flags |= MLX5_ETH_WQE_L3_INNER_CSUM |
> MLX5_ETH_WQE_L4_INNER_CSUM;
> sq->stats->csum_partial_inner++;
> } else {
> eseg->cs_flags |= MLX5_ETH_WQE_L4_CSUM;
> sq->stats->csum_partial++;
> }
>
> How would you generalize that into csum api that will work across NICs ?
>
> My answer stands: you cannot.
>
> My proposal again:
> add driver specifc kfuncs and hooks for things like csum.
>
> Kuba,
> since you nacked driver specific stuff please suggest a way to unblock this stalemate.
I hope I'm not misremembering but I think I suggested at the beginning
to create a structure describing packet geometry and requested offloads,
and for the prog fill that in.
All operating systems I know end up doing that, we'll end up doing
that as well. The question is whether we're willing to learn from
experience or prefer to go on a wild ride first...
next prev parent reply other threads:[~2023-07-12 0:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-07 19:29 [xdp-hints] [RFC bpf-next v3 00/14] bpf: Netdev TX metadata Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 01/14] bpf: Rename some xdp-metadata functions into dev-bound Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 02/14] bpf: Make it easier to add new metadata kfunc Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 03/14] xsk: Support XDP_TX_METADATA_LEN Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 04/14] bpf: Implement devtx hook points Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 05/14] bpf: Implement devtx timestamp kfunc Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 06/14] net: veth: Implement devtx timestamp kfuncs Stanislav Fomichev
2023-07-07 19:29 ` [xdp-hints] [RFC bpf-next v3 07/14] bpf: Introduce tx checksum devtx kfuncs Stanislav Fomichev
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 08/14] net: veth: Implement devtx tx checksum Stanislav Fomichev
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 09/14] net/mlx5e: Implement devtx kfuncs Stanislav Fomichev
2023-07-11 22:56 ` [xdp-hints] " Alexei Starovoitov
2023-07-11 23:24 ` Stanislav Fomichev
2023-07-11 23:45 ` Alexei Starovoitov
2023-07-12 0:14 ` Stanislav Fomichev
2023-07-12 2:50 ` Alexei Starovoitov
2023-07-12 3:29 ` Stanislav Fomichev
2023-07-12 4:59 ` Alexei Starovoitov
2023-07-12 5:36 ` Stanislav Fomichev
2023-07-12 15:16 ` Willem de Bruijn
2023-07-12 16:28 ` Willem de Bruijn
2023-07-12 19:03 ` Alexei Starovoitov
2023-07-12 19:11 ` Willem de Bruijn
2023-07-12 19:42 ` Alexei Starovoitov
2023-07-12 20:09 ` Jakub Kicinski
2023-07-12 20:53 ` Stanislav Fomichev
2023-07-12 0:32 ` Jakub Kicinski [this message]
2023-07-12 2:37 ` Alexei Starovoitov
2023-07-12 3:07 ` Jakub Kicinski
2023-07-12 3:23 ` Alexei Starovoitov
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 10/14] selftests/xsk: Support XDP_TX_METADATA_LEN Stanislav Fomichev
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 11/14] selftests/bpf: Add helper to query current netns cookie Stanislav Fomichev
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 12/14] selftests/bpf: Add csum helpers Stanislav Fomichev
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 13/14] selftests/bpf: Extend xdp_metadata with devtx kfuncs Stanislav Fomichev
2023-07-07 19:30 ` [xdp-hints] [RFC bpf-next v3 14/14] selftests/bpf: Extend xdp_hw_metadata " Stanislav Fomichev
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