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From: John Fastabend <john.fastabend@gmail.com>
To: Stanislav Fomichev <sdf@google.com>, bpf@vger.kernel.org
Cc: 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, sdf@google.com,
	haoluo@google.com, jolsa@kernel.org,
	David Ahern <dsahern@gmail.com>, Jakub Kicinski <kuba@kernel.org>,
	Willem de Bruijn <willemb@google.com>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Anatoly Burakov <anatoly.burakov@intel.com>,
	Alexander Lobakin <alexandr.lobakin@intel.com>,
	Magnus Karlsson <magnus.karlsson@gmail.com>,
	Maryam Tahhan <mtahhan@redhat.com>,
	xdp-hints@xdp-project.net, netdev@vger.kernel.org
Subject: [xdp-hints] Re: [RFC bpf-next v2 04/14] veth: Support rx timestamp metadata for xdp
Date: Wed, 09 Nov 2022 16:25:56 -0800	[thread overview]
Message-ID: <636c4514917fa_13c168208d0@john.notmuch> (raw)
In-Reply-To: <20221104032532.1615099-5-sdf@google.com>

Stanislav Fomichev wrote:
> xskxceiver conveniently setups up veth pairs so it seems logical
> to use veth as an example for some of the metadata handling.
> 
> We timestamp skb right when we "receive" it, store its
> pointer in new veth_xdp_buff wrapper and generate BPF bytecode to
> reach it from the BPF program.
> 
> This largely follows the idea of "store some queue context in
> the xdp_buff/xdp_frame so the metadata can be reached out
> from the BPF program".
> 

[...]

>  	orig_data = xdp->data;
>  	orig_data_end = xdp->data_end;
> +	vxbuf.skb = skb;
>  
>  	act = bpf_prog_run_xdp(xdp_prog, xdp);
>  
> @@ -942,6 +946,7 @@ static int veth_xdp_rcv(struct veth_rq *rq, int budget,
>  			struct sk_buff *skb = ptr;
>  
>  			stats->xdp_bytes += skb->len;
> +			__net_timestamp(skb);

Just getting to reviewing in depth a bit more. But we hit veth with lots of
packets in some configurations I don't think we want to add a __net_timestamp
here when vast majority of use cases will have no need for timestamp on veth
device. I didn't do a benchmark but its not free.

If there is a real use case for timestamping on veth we could do it through
a XDP program directly? Basically fallback for devices without hw timestamps.
Anyways I need the helper to support hardware without time stamping.

Not sure if this was just part of the RFC to explore BPF programs or not.

>  			skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
>  			if (skb) {
>  				if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))

  parent reply	other threads:[~2022-11-10  0:26 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-04  3:25 [xdp-hints] [RFC bpf-next v2 00/14] xdp: hints via kfuncs Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 01/14] bpf: Introduce bpf_patch Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 02/14] bpf: Support inlined/unrolled kfuncs for xdp metadata Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 03/14] veth: Introduce veth_xdp_buff wrapper for xdp_buff Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 04/14] veth: Support rx timestamp metadata for xdp Stanislav Fomichev
2022-11-09 11:21   ` [xdp-hints] " Toke Høiland-Jørgensen
2022-11-09 21:34     ` Stanislav Fomichev
2022-11-10  0:25   ` John Fastabend [this message]
2022-11-10  1:02     ` Stanislav Fomichev
2022-11-10  1:35       ` John Fastabend
2022-11-10  6:44         ` Stanislav Fomichev
2022-11-10 17:39           ` John Fastabend
2022-11-10 18:52             ` Stanislav Fomichev
2022-11-11 10:41             ` Jesper Dangaard Brouer
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 05/14] selftests/bpf: Verify xdp_metadata xdp->af_xdp path Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 06/14] xdp: Carry over xdp metadata into skb context Stanislav Fomichev
2022-11-07 22:01   ` [xdp-hints] " Martin KaFai Lau
2022-11-08 21:54     ` Stanislav Fomichev
2022-11-09  3:07       ` Martin KaFai Lau
2022-11-09  4:19         ` Martin KaFai Lau
2022-11-09 11:10           ` Toke Høiland-Jørgensen
2022-11-09 18:22             ` Martin KaFai Lau
2022-11-09 21:33               ` Stanislav Fomichev
2022-11-10  0:13                 ` Martin KaFai Lau
2022-11-10  1:02                   ` Stanislav Fomichev
2022-11-10 14:26                     ` Toke Høiland-Jørgensen
2022-11-10 18:52                       ` Stanislav Fomichev
2022-11-10 23:14                         ` Toke Høiland-Jørgensen
2022-11-10 23:52                           ` Stanislav Fomichev
2022-11-11  0:10                             ` Toke Høiland-Jørgensen
2022-11-11  0:45                               ` Martin KaFai Lau
2022-11-11  9:37                                 ` Toke Høiland-Jørgensen
2022-11-11  0:33                             ` Martin KaFai Lau
2022-11-11  0:57                               ` Stanislav Fomichev
2022-11-11  1:26                                 ` Martin KaFai Lau
2022-11-11  9:41                                   ` Toke Høiland-Jørgensen
2022-11-10 23:58                         ` Martin KaFai Lau
2022-11-11  0:20                           ` Stanislav Fomichev
2022-11-10 14:19               ` Toke Høiland-Jørgensen
2022-11-10 19:04                 ` Martin KaFai Lau
2022-11-10 23:29                   ` Toke Høiland-Jørgensen
2022-11-11  1:39                     ` Martin KaFai Lau
2022-11-11  9:44                       ` Toke Høiland-Jørgensen
2022-11-10  1:26             ` John Fastabend
2022-11-10 14:32               ` Toke Høiland-Jørgensen
2022-11-10 17:30                 ` John Fastabend
2022-11-10 22:49                   ` Toke Høiland-Jørgensen
2022-11-10  1:09   ` John Fastabend
2022-11-10  6:44     ` Stanislav Fomichev
2022-11-10 21:21       ` David Ahern
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 07/14] selftests/bpf: Verify xdp_metadata xdp->skb path Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 08/14] bpf: Helper to simplify calling kernel routines from unrolled kfuncs Stanislav Fomichev
2022-11-05  0:40   ` [xdp-hints] " Alexei Starovoitov
2022-11-05  2:18     ` Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 09/14] ice: Introduce ice_xdp_buff wrapper for xdp_buff Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 10/14] ice: Support rx timestamp metadata for xdp Stanislav Fomichev
2022-11-04 14:35   ` [xdp-hints] " Alexander Lobakin
2022-11-04 18:21     ` Stanislav Fomichev
2022-11-07 17:11       ` Alexander Lobakin
2022-11-07 19:10         ` Stanislav Fomichev
2022-12-15 11:54   ` Larysa Zaremba
2022-12-15 14:29     ` Toke Høiland-Jørgensen
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 11/14] mlx4: Introduce mlx4_xdp_buff wrapper for xdp_buff Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 12/14] mxl4: Support rx timestamp metadata for xdp Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 13/14] bnxt: Introduce bnxt_xdp_buff wrapper for xdp_buff Stanislav Fomichev
2022-11-04  3:25 ` [xdp-hints] [RFC bpf-next v2 14/14] bnxt: Support rx timestamp metadata for xdp Stanislav Fomichev

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