From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jason Xing <kerneljasonxing@gmail.com>,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, dsahern@kernel.org,
willemdebruijn.kernel@gmail.com, willemb@google.com,
ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org,
yonghong.song@linux.dev, john.fastabend@gmail.com,
kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com,
jolsa@kernel.org, shuah@kernel.org, ykolal@fb.com
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
Jason Xing <kerneljasonxing@gmail.com>
Subject: Re: [PATCH bpf-next v12 12/12] selftests/bpf: add simple bpf tests in the tx path for timestamping feature
Date: Tue, 18 Feb 2025 09:25:12 -0500 [thread overview]
Message-ID: <67b49848ec47c_10d6a329425@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20250218050125.73676-13-kerneljasonxing@gmail.com>
Jason Xing wrote:
> BPF program calculates a couple of latency deltas between each tx
> timestamping callbacks. It can be used in the real world to diagnose
> the kernel behaviour in the tx path.
>
> Check the safety issues by accessing a few bpf calls in
> bpf_test_access_bpf_calls() which are implemented in the patch 3 and 4.
>
> Check if the bpf timestamping can co-exist with socket timestamping.
>
> There remains a few realistic things[1][2] to highlight:
> 1. in general a packet may pass through multiple qdiscs. For instance
> with bonding or tunnel virtual devices in the egress path.
> 2. packets may be resent, in which case an ACK might precede a repeat
> SCHED and SND.
> 3. erroneous or malicious peers may also just never send an ACK.
>
> [1]: https://lore.kernel.org/all/67a389af981b0_14e0832949d@willemb.c.googlers.com.notmuch/
> [2]: https://lore.kernel.org/all/c329a0c1-239b-4ca1-91f2-cb30b8dd2f6a@linux.dev/
>
> Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
prev parent reply other threads:[~2025-02-18 14:25 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-18 5:01 [PATCH bpf-next v12 00/12] net-timestamp: bpf extension to equip applications transparently Jason Xing
2025-02-18 5:01 ` [PATCH bpf-next v12 01/12] bpf: add networking timestamping support to bpf_get/setsockopt() Jason Xing
2025-02-18 14:22 ` Willem de Bruijn
2025-02-18 21:55 ` Martin KaFai Lau
2025-02-18 23:43 ` Jason Xing
2025-02-19 2:32 ` Willem de Bruijn
2025-02-19 6:29 ` Jason Xing
2025-02-19 15:12 ` Willem de Bruijn
2025-02-20 0:04 ` Jason Xing
2025-02-20 2:46 ` Willem de Bruijn
2025-02-19 7:03 ` Jason Xing
2025-02-19 19:48 ` Martin KaFai Lau
2025-02-20 0:05 ` Jason Xing
2025-02-18 5:01 ` [PATCH bpf-next v12 02/12] bpf: prepare the sock_ops ctx and call bpf prog for TX timestamping Jason Xing
2025-02-18 5:01 ` [PATCH bpf-next v12 03/12] bpf: prevent unsafe access to the sock fields in the BPF timestamping callback Jason Xing
2025-02-18 5:01 ` [PATCH bpf-next v12 04/12] bpf: disable unsafe helpers in TX timestamping callbacks Jason Xing
2025-02-18 5:01 ` [PATCH bpf-next v12 05/12] net-timestamp: prepare for isolating two modes of SO_TIMESTAMPING Jason Xing
2025-02-18 14:23 ` Willem de Bruijn
2025-02-18 5:01 ` [PATCH bpf-next v12 06/12] bpf: add BPF_SOCK_OPS_TS_SCHED_OPT_CB callback Jason Xing
2025-02-18 14:23 ` Willem de Bruijn
2025-02-18 5:01 ` [PATCH bpf-next v12 07/12] bpf: add BPF_SOCK_OPS_TS_SW_OPT_CB callback Jason Xing
2025-02-18 14:23 ` Willem de Bruijn
2025-02-18 5:01 ` [PATCH bpf-next v12 08/12] bpf: add BPF_SOCK_OPS_TS_HW_OPT_CB callback Jason Xing
2025-02-18 14:23 ` Willem de Bruijn
2025-02-18 5:01 ` [PATCH bpf-next v12 09/12] bpf: add BPF_SOCK_OPS_TS_ACK_OPT_CB callback Jason Xing
2025-02-18 14:24 ` Willem de Bruijn
2025-02-18 5:01 ` [PATCH bpf-next v12 10/12] bpf: add BPF_SOCK_OPS_TS_SND_CB callback Jason Xing
2025-02-18 14:24 ` Willem de Bruijn
2025-02-20 2:55 ` Willem de Bruijn
2025-02-20 3:15 ` Jason Xing
2025-02-20 4:31 ` Jason Xing
2025-02-20 15:28 ` Willem de Bruijn
2025-02-18 5:01 ` [PATCH bpf-next v12 11/12] bpf: support selective sampling for bpf timestamping Jason Xing
2025-02-18 5:01 ` [PATCH bpf-next v12 12/12] selftests/bpf: add simple bpf tests in the tx path for timestamping feature Jason Xing
2025-02-18 14:25 ` Willem de Bruijn [this message]
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