[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <87sfihxfz8.fsf@toke.dk>
Date: Fri, 18 Nov 2022 01:29:15 +0100
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc: Stanislav Fomichev <sdf@...gle.com>,
John Fastabend <john.fastabend@...il.com>,
Martin KaFai Lau <martin.lau@...ux.dev>,
bpf <bpf@...r.kernel.org>, Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>,
Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
KP Singh <kpsingh@...nel.org>, Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>, David Ahern <dsahern@...il.com>,
Jakub Kicinski <kuba@...nel.org>,
Willem de Bruijn <willemb@...gle.com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Anatoly Burakov <anatoly.burakov@...el.com>,
Alexander Lobakin <alexandr.lobakin@...el.com>,
Magnus Karlsson <magnus.karlsson@...il.com>,
Maryam Tahhan <mtahhan@...hat.com>, xdp-hints@...-project.net,
Network Development <netdev@...r.kernel.org>
Subject: Re: [xdp-hints] Re: [PATCH bpf-next 05/11] veth: Support rx
timestamp metadata for xdp
Alexei Starovoitov <alexei.starovoitov@...il.com> writes:
> On Thu, Nov 17, 2022 at 3:46 PM Toke Høiland-Jørgensen <toke@...hat.com> wrote:
>>
>> >
>> > Ack. I can replace the unrolling with something that just resolves
>> > "generic" kfuncs to the per-driver implementation maybe? That would at
>> > least avoid netdev->ndo_kfunc_xxx indirect calls at runtime..
>>
>> As stated above, I think we should keep the unrolling. If we end up with
>> an actual CALL instruction for every piece of metadata that's going to
>> suck performance-wise; unrolling is how we keep this fast enough! :)
>
> Let's start with pure kfuncs without requiring drivers
> to provide corresponding bpf asm.
> If pure kfuncs will indeed turn out to be perf limiting
> then we'll decide on how to optimize them.
I'm ~90% sure we'll need that optimisation, but OK, we can start from a
baseline of having them be function calls...
-Toke
Powered by blists - more mailing lists