From: Yonghong Song <yhs@fb.com>
To: Martin Lau <kafai@fb.com>, "bpf@vger.kernel.org" <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>,
Kernel Team <Kernel-team@fb.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next v2 07/11] bpf: tcp: Support tcp_congestion_ops in bpf
Date: Mon, 23 Dec 2019 20:18:25 +0000 [thread overview]
Message-ID: <c1e908ca-917b-3d65-1d45-892b0f63ff3c@fb.com> (raw)
In-Reply-To: <20191221062611.1183363-1-kafai@fb.com>
On 12/20/19 10:26 PM, Martin KaFai Lau wrote:
> This patch makes "struct tcp_congestion_ops" to be the first user
> of BPF STRUCT_OPS. It allows implementing a tcp_congestion_ops
> in bpf.
>
> The BPF implemented tcp_congestion_ops can be used like
> regular kernel tcp-cc through sysctl and setsockopt. e.g.
> [root@arch-fb-vm1 bpf]# sysctl -a | egrep congestion
> net.ipv4.tcp_allowed_congestion_control = reno cubic bpf_cubic
> net.ipv4.tcp_available_congestion_control = reno bic cubic bpf_cubic
> net.ipv4.tcp_congestion_control = bpf_cubic
>
> There has been attempt to move the TCP CC to the user space
> (e.g. CCP in TCP). The common arguments are faster turn around,
> get away from long-tail kernel versions in production...etc,
> which are legit points.
>
> BPF has been the continuous effort to join both kernel and
> userspace upsides together (e.g. XDP to gain the performance
> advantage without bypassing the kernel). The recent BPF
> advancements (in particular BTF-aware verifier, BPF trampoline,
> BPF CO-RE...) made implementing kernel struct ops (e.g. tcp cc)
> possible in BPF. It allows a faster turnaround for testing algorithm
> in the production while leveraging the existing (and continue growing)
> BPF feature/framework instead of building one specifically for
> userspace TCP CC.
>
> This patch allows write access to a few fields in tcp-sock
> (in bpf_tcp_ca_btf_struct_access()).
>
> The optional "get_info" is unsupported now. It can be added
> later. One possible way is to output the info with a btf-id
> to describe the content.
>
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Ack from bpf/btf perspective.
Acked-by: Yonghong Song <yhs@fb.com>
next prev parent reply other threads:[~2019-12-23 20:18 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-21 6:25 [PATCH bpf-next v2 00/11] Introduce BPF STRUCT_OPS Martin KaFai Lau
2019-12-21 6:25 ` [PATCH bpf-next v2 01/11] bpf: Save PTR_TO_BTF_ID register state when spilling to stack Martin KaFai Lau
2019-12-21 6:25 ` [PATCH bpf-next v2 02/11] bpf: Avoid storing modifier to info->btf_id Martin KaFai Lau
2019-12-21 6:26 ` [PATCH bpf-next v2 03/11] bpf: Add enum support to btf_ctx_access() Martin KaFai Lau
2019-12-21 6:26 ` [PATCH bpf-next v2 04/11] bpf: Support bitfield read access in btf_struct_access Martin KaFai Lau
2019-12-23 7:49 ` Yonghong Song
2019-12-23 20:05 ` Andrii Nakryiko
2019-12-23 21:21 ` Yonghong Song
2019-12-21 6:26 ` [PATCH bpf-next v2 05/11] bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS Martin KaFai Lau
2019-12-23 19:33 ` Yonghong Song
2019-12-23 20:29 ` Andrii Nakryiko
2019-12-23 22:29 ` Martin Lau
2019-12-23 22:55 ` Andrii Nakryiko
2019-12-24 11:46 ` kbuild test robot
2019-12-21 6:26 ` [PATCH bpf-next v2 06/11] bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS Martin KaFai Lau
2019-12-23 19:57 ` Yonghong Song
2019-12-23 21:44 ` Andrii Nakryiko
2019-12-23 22:15 ` Martin Lau
2019-12-27 6:16 ` Martin Lau
2019-12-23 23:05 ` Andrii Nakryiko
2019-12-28 1:47 ` Martin Lau
2019-12-28 2:24 ` Andrii Nakryiko
2019-12-28 5:16 ` Martin Lau
2019-12-24 12:28 ` kbuild test robot
2019-12-21 6:26 ` [PATCH bpf-next v2 07/11] bpf: tcp: Support tcp_congestion_ops in bpf Martin KaFai Lau
2019-12-23 20:18 ` Yonghong Song [this message]
2019-12-23 23:20 ` Andrii Nakryiko
2019-12-24 7:16 ` kbuild test robot
2019-12-24 13:06 ` kbuild test robot
2019-12-21 6:26 ` [PATCH bpf-next v2 08/11] bpf: Add BPF_FUNC_tcp_send_ack helper Martin KaFai Lau
2019-12-21 6:26 ` [PATCH bpf-next v2 09/11] bpf: Synch uapi bpf.h to tools/ Martin KaFai Lau
2019-12-21 6:26 ` [PATCH bpf-next v2 10/11] bpf: libbpf: Add STRUCT_OPS support Martin KaFai Lau
2019-12-23 19:54 ` Andrii Nakryiko
2019-12-26 22:47 ` Martin Lau
2019-12-21 6:26 ` [PATCH bpf-next v2 11/11] bpf: Add bpf_dctcp example Martin KaFai Lau
2019-12-23 23:26 ` Andrii Nakryiko
2019-12-24 1:31 ` Martin Lau
2019-12-24 7:01 ` Andrii Nakryiko
2019-12-24 7:32 ` Martin Lau
2019-12-24 16:50 ` Martin Lau
2019-12-26 19:02 ` Andrii Nakryiko
2019-12-26 20:25 ` Martin Lau
2019-12-26 20:48 ` Andrii Nakryiko
2019-12-26 22:20 ` Martin Lau
2019-12-26 22:25 ` Andrii Nakryiko
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