netdev - Re: [PATCH bpf-next] samples/bpf: add xdp_redirect_map with xdp

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Message-ID: <20201110152510.2a7fa65c@carbon>
Date:   Tue, 10 Nov 2020 15:25:10 +0100
From:   Jesper Dangaard Brouer <brouer@...hat.com>
To:     Hangbin Liu <liuhangbin@...il.com>
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org,
        Daniel Borkmann <daniel@...earbox.net>,
        John Fastabend <john.fastabend@...il.com>,
        Toke Høiland-Jørgensen <toke@...hat.com>,
        Tariq Toukan <tariqt@...lanox.com>, brouer@...hat.com,
        Jakub Kicinski <kuba@...nel.org>
Subject: Re: [PATCH bpf-next] samples/bpf: add xdp_redirect_map with
 xdp_prog support

On Tue, 10 Nov 2020 20:46:39 +0800
Hangbin Liu <liuhangbin@...il.com> wrote:

> This patch add running xdp program on egress interface support for
> xdp_redirect_map sample. The new prog will change the IP ttl based
> on egress ifindex.
> 
> Signed-off-by: Hangbin Liu <liuhangbin@...il.com>
> ---
>  samples/bpf/xdp_redirect_map_kern.c | 74 ++++++++++++++++++++++++++++-
>  samples/bpf/xdp_redirect_map_user.c | 21 ++++----

Hmmm... I don't think is it a good idea to modify xdp_redirect_map this way.

The xdp_redirect_map is used for comparative benchmarking and
mentioned+used in scientific articles.  As far as I can see, this
change will default slowdown xdp_redirect_map performance, right?

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer