From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Daniel Borkmann" <daniel@iogearbox.net>,
"Cong Wang" <xiyou.wangcong@gmail.com>, bpf <bpf@vger.kernel.org>,
"Alexei Starovoitov" <ast@kernel.org>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@kernel.org>,
"Vlad Buslov" <vladbu@nvidia.com>,
"Jiri Pirko" <jiri@resnulli.us>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Joe Stringer" <joe@cilium.io>,
"Quentin Monnet" <quentin@isovalent.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Linux Kernel Network Developers" <netdev@vger.kernel.org>,
"Marcelo Ricardo Leitner" <mleitner@redhat.com>
Subject: Re: [PATCH RFC bpf-next 0/7] Add bpf_link based TC-BPF API
Date: Wed, 16 Jun 2021 21:02:09 +0530 [thread overview]
Message-ID: <20210616153209.pejkgb3iieu6idqq@apollo> (raw)
In-Reply-To: <7248dc4e-8c07-a25d-5ac3-c4c106b7a266@mojatatu.com>
On Wed, Jun 16, 2021 at 08:10:55PM IST, Jamal Hadi Salim wrote:
> On 2021-06-15 7:07 p.m., Daniel Borkmann wrote:
> > On 6/13/21 11:10 PM, Jamal Hadi Salim wrote:
>
> [..]
>
> > >
> > > I look at it from the perspective that if i can run something with
> > > existing tc loading mechanism then i should be able to do the same
> > > with the new (libbpf) scheme.
> >
> > The intention is not to provide a full-blown tc library (that could be
> > subject to a
> > libtc or such), but rather to only have libbpf abstract the tc related
> > API that is
> > most /relevant/ for BPF program development and /efficient/ in terms of
> > execution in
> > fast-path while at the same time providing a good user experience from
> > the API itself.
> >
> > That is, simple to use and straight forward to explain to folks with
> > otherwise zero
> > experience of tc. The current implementation does all that, and from
> > experience with
> > large BPF programs managed via cls_bpf that is all that is actually
> > needed from tc
> > layer perspective. The ability to have multi programs (incl. priorities)
> > is in the
> > existing libbpf API as well.
> >
>
> Which is a fair statement, but if you take away things that work fine
> with current iproute2 loading I have no motivation to migrate at all.
> Its like that saying of "throwing out the baby with the bathwater".
> I want my baby.
>
> In particular, here's a list from Kartikeya's implementation:
>
> 1) Direct action mode only
> 2) Protocol ETH_P_ALL only
> 3) Only at chain 0
> 4) No block support
>
Block is supported, you just need to set TCM_IFINDEX_MAGIC_BLOCK as ifindex and
parent as the block index. There isn't anything more to it than that from libbpf
side (just specify BPF_TC_CUSTOM enum).
What I meant was that hook_create doesn't support specifying the ingress/egress
block when creating clsact, but that typically isn't a problem because qdiscs
for shared blocks would be set up together prior to the attachment anyway.
> I think he said priority is supported but was also originally on that
> list.
> When we discussed at the meetup it didnt seem these cost anything
> in terms of code complexity or usability of the API.
>
> 1) We use non-DA mode, so i cant live without that (and frankly ebpf
> has challenges adding complex code blocks).
>
> 2) We also use different protocols when i need to
> (yes, you can do the filtering in the bpf code - but why impose that
> if the cost of adding it is simple? and of course it is cheaper to do
> the check outside of ebpf)
> 3) We use chains outside of zero
>
> 4) So far we dont use block support but certainly my recent experiences
> in a deployment shows that we need to group netdevices more often than
> i thought was necessary. So if i could express one map shared by
> multiple netdevices it should cut down the user space complexity.
>
> cheers,
> jamal
--
Kartikeya
next prev parent reply other threads:[~2021-06-16 15:33 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-28 19:59 [PATCH RFC bpf-next 0/7] Add bpf_link based TC-BPF API Kumar Kartikeya Dwivedi
2021-05-28 19:59 ` [PATCH RFC bpf-next 1/7] net: sched: refactor cls_bpf creation code Kumar Kartikeya Dwivedi
2021-05-28 19:59 ` [PATCH RFC bpf-next 2/7] bpf: export bpf_link functions for modules Kumar Kartikeya Dwivedi
2021-05-28 19:59 ` [PATCH RFC bpf-next 3/7] net: sched: add bpf_link API for bpf classifier Kumar Kartikeya Dwivedi
2021-06-02 20:56 ` Andrii Nakryiko
2021-05-28 19:59 ` [PATCH RFC bpf-next 4/7] net: sched: add lightweight update path for cls_bpf Kumar Kartikeya Dwivedi
2021-05-28 19:59 ` [PATCH RFC bpf-next 5/7] tools: bpf.h: sync with kernel sources Kumar Kartikeya Dwivedi
2021-05-28 19:59 ` [PATCH RFC bpf-next 6/7] libbpf: add bpf_link based TC-BPF management API Kumar Kartikeya Dwivedi
2021-06-02 21:03 ` Andrii Nakryiko
2021-05-28 19:59 ` [PATCH RFC bpf-next 7/7] libbpf: add selftest for " Kumar Kartikeya Dwivedi
2021-06-02 21:09 ` [PATCH RFC bpf-next 0/7] Add bpf_link based TC-BPF API Andrii Nakryiko
2021-06-02 21:45 ` Kumar Kartikeya Dwivedi
2021-06-02 23:50 ` Alexei Starovoitov
2021-06-04 6:43 ` Kumar Kartikeya Dwivedi
2021-06-06 23:37 ` Cong Wang
2021-06-07 3:37 ` Kumar Kartikeya Dwivedi
2021-06-07 5:18 ` Cong Wang
2021-06-07 6:07 ` Kumar Kartikeya Dwivedi
2021-06-08 2:00 ` Cong Wang
2021-06-08 7:19 ` Kumar Kartikeya Dwivedi
2021-06-08 15:39 ` Alexei Starovoitov
2021-06-11 2:10 ` Cong Wang
2021-06-11 2:00 ` Cong Wang
2021-06-13 2:53 ` Kumar Kartikeya Dwivedi
2021-06-13 20:27 ` Jamal Hadi Salim
2021-06-13 20:34 ` Kumar Kartikeya Dwivedi
2021-06-13 21:10 ` Jamal Hadi Salim
2021-06-14 13:03 ` Marcelo Ricardo Leitner
2021-06-15 23:07 ` Daniel Borkmann
2021-06-16 14:40 ` Jamal Hadi Salim
2021-06-16 15:32 ` Kumar Kartikeya Dwivedi [this message]
2021-06-16 16:00 ` Daniel Borkmann
2021-06-18 11:40 ` Jamal Hadi Salim
2021-06-18 14:38 ` Alexei Starovoitov
2021-06-18 14:50 ` Jamal Hadi Salim
2021-06-18 16:23 ` Alexei Starovoitov
2021-06-18 16:41 ` Jamal Hadi Salim
2021-06-18 22:42 ` Daniel Borkmann
2021-06-21 13:55 ` Jamal Hadi Salim
2021-06-15 4:33 ` Cong Wang
2021-06-15 11:54 ` Toke Høiland-Jørgensen
2021-06-15 23:44 ` Daniel Borkmann
2021-06-16 12:03 ` Toke Høiland-Jørgensen
2021-06-16 15:33 ` Jamal Hadi Salim
2021-06-13 3:08 ` Kumar Kartikeya Dwivedi
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