From: Jakub Kicinski <kubakici@wp.pl>
To: Tom Herbert <tom@herbertland.com>
Cc: Alexei Starovoitov <ast@fb.com>,
"David S. Miller" <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Kernel Team <kernel-team@fb.com>,
Tariq Toukan <tariqt@mellanox.com>,
Brenden Blanco <bblanco@plumgrid.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Jesper Dangaard Brouer <brouer@redhat.com>
Subject: Re: [PATCH RFC 1/3] xdp: Infrastructure to generalize XDP
Date: Wed, 21 Sep 2016 19:54:50 +0100 [thread overview]
Message-ID: <20160921195450.4c5feb4a@jkicinski-Precision-T1700> (raw)
In-Reply-To: <CALx6S34c6Mz=YpbiPcVNe38wTkxfjB9SWxaqtz1LivLeGzssRQ@mail.gmail.com>
On Wed, 21 Sep 2016 11:50:06 -0700, Tom Herbert wrote:
> On Wed, Sep 21, 2016 at 11:45 AM, Jakub Kicinski <kubakici@wp.pl> wrote:
> > On Wed, 21 Sep 2016 10:39:40 -0700, Tom Herbert wrote:
> >> On Wed, Sep 21, 2016 at 10:26 AM, Jakub Kicinski <kubakici@wp.pl> wrote:
> >> > On Tue, 20 Sep 2016 17:01:39 -0700, Alexei Starovoitov wrote:
> >> >> > - Reduces the amount of code and complexity needed in drivers to
> >> >> > manage XDP
> >> >>
> >> >> hmm:
> >> >> 534 insertions(+), 144 deletions(-)
> >> >> looks like increase in complexity instead.
> >> >
> >> > and more to come to tie this with HW offloads.
> >>
> >> The amount of driver code did decrease with these patches:
> >>
> >> drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 64 ++++----------------------
> >> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 25 ++++------
> >> drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 -
> >>
> >> Minimizing complexity being added to drivers for XDP is critical since
> >> we basically asking every driver to replicate the function. This
> >> property also should also apply to HW offloads, the more complexity we
> >> can abstract out drivers into a common backend infrastructure the
> >> better for supporting across different drivers.
> >
> > I'm in the middle of writing/testing XDP support for the Netronome's
> > driver and generic infra is very much appreciated ;) In my experience
> > the 50 lines of code which are required for assigning the programs and
> > freeing them aren't really a big deal, though.
> >
>
> 50 lines in one driver is not a big deal, 50 lines in a hundred
> drivers is! I learned this lesson in BQL which was well abstracted out
> to be minimally invasive but we still saw many issues because of the
> pecularities of different drivers.
Agreed, I just meant to say that splitting rings and rewritting RX path
to behave differently for XDP vs non-XDP case is way more brain
consuming than a bit of boilerplate code so if anyone could solve those
two it would be much appreciated :) My main point was what I wrote
below, though.
> > Let's also separate putting xdp_prog in netdevice/napi_struct from the
> > generic hook infra. All the simplifications to the driver AFAICS come
> > from the former. If everyone is fine with growing napi_struct we can do
> > that but IMHO this is not an argument for the generic infra :)
next prev parent reply other threads:[~2016-09-21 18:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 22:00 [PATCH RFC 0/3] xdp: Generalize XDP Tom Herbert
2016-09-20 22:00 ` [PATCH RFC 1/3] xdp: Infrastructure to generalize XDP Tom Herbert
2016-09-20 22:37 ` Eric Dumazet
2016-09-20 22:40 ` Tom Herbert
2016-09-20 22:44 ` Thomas Graf
2016-09-20 22:49 ` Tom Herbert
2016-09-20 23:09 ` Thomas Graf
2016-09-20 23:18 ` Tom Herbert
2016-09-20 23:43 ` Thomas Graf
2016-09-20 23:59 ` Tom Herbert
2016-09-21 0:13 ` Alexei Starovoitov
2016-09-21 11:55 ` Thomas Graf
2016-09-21 14:19 ` Tom Herbert
2016-09-21 14:48 ` Thomas Graf
2016-09-21 15:08 ` Tom Herbert
2016-09-21 19:56 ` Jesper Dangaard Brouer
2016-09-22 13:14 ` Jesper Dangaard Brouer
2016-09-22 14:46 ` Eric Dumazet
2016-09-21 15:39 ` Alexei Starovoitov
2016-09-21 17:26 ` Jakub Kicinski
2016-09-20 23:22 ` Daniel Borkmann
2016-09-21 0:01 ` Alexei Starovoitov
2016-09-21 6:39 ` Jesper Dangaard Brouer
2016-09-21 8:42 ` Daniel Borkmann
2016-09-21 15:44 ` Alexei Starovoitov
2016-09-21 17:26 ` Jakub Kicinski
2016-09-21 17:39 ` Tom Herbert
2016-09-21 18:45 ` Jakub Kicinski
2016-09-21 18:50 ` Tom Herbert
2016-09-21 18:54 ` Jakub Kicinski [this message]
2016-09-21 18:58 ` Thomas Graf
2016-09-23 11:13 ` Jamal Hadi Salim
2016-09-23 13:00 ` Jesper Dangaard Brouer
2016-09-23 14:26 ` Alexei Starovoitov
2016-09-25 11:32 ` Jamal Hadi Salim
2016-09-23 14:14 ` Tom Herbert
2016-09-25 12:29 ` Jamal Hadi Salim
2016-09-20 22:00 ` [PATCH RFC 2/3] mlx4: Change XDP/BPF to use generic XDP infrastructure Tom Herbert
2016-09-20 22:00 ` [PATCH RFC 3/3] netdevice: Remove obsolete xdp_netdev_command Tom Herbert
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