Date:	Fri, 2 Jan 2015 11:04:02 +0200
From:	Rami Rosen <roszenrami@...il.com>
To:	sfeldma@...il.com
Cc:	Netdev <netdev@...r.kernel.org>, jiri@...nulli.us,
	john.fastabend@...il.com, tgraf@...g.ch, jhs@...atatu.com,
	andy@...yhouse.net, roopa@...ulusnetworks.com
Subject: Re: [PATCH net-next 0/3] swdev: add IPv4 routing offload

Hi, Scott,

Good work!

You say that currently the rocker driver support only unicast singlepath IPv4.
If I understand correctly, IPv4 packets with tos !=0 are skipped in
the current rocker implementation of the ndo_sw_parent_fib_ipv4_add()
callback. I am referring to the rocker_port_fib_ipv4_skip() method:

if (tos != 0)
     return -EOPNOTSUPP;

see:
https://github.com/jpirko/net-next-rocker/blob/master/drivers/net/ethernet/rocker/rocker.c#L3701

Is there a reason for this? (The NDO that you suggest,
ndo_sw_parent_fib_ipv4_add(), has the tos as a parameter, so from this
aspect there is no problem).

Regards,
Rami Rosen


On Fri, Jan 2, 2015 at 5:29 AM,  <sfeldma@...il.com> wrote:
> From: Scott Feldman <sfeldma@...il.com>
>
> This patch set adds L3 routing offload support for IPv4 routes.  The idea is to
> mirror routes installed in the kernel's FIB down to a hardware switch device to
> offload the data forwarding path for L3.  Only the data forwarding path is
> intercepted.  Control and management of the kernel's FIB remains with the
> kernel.
>
> A couple of new ndo ops (ndo_switch_fib_ipv4_add/del) are added to the swdev
> model to add/remove FIB entries to/from the offload device.  The ops are called
> from the core IPv4 FIB code directly.  Just before the FIB entry is installed
> in the kernel's FIB, the swdev device driver gets a chance at the FIB entry
> (assuming the swdev driver implements the new ndo ops).  This is a synchronous
> call in the RTM_NEWROUTE path, and the swdev has the option to fail the
> install, which means the FIB entry is not installed in swdev or the kernel, and
> the user is notified of the failure.  The swdev driver also has the option to
> return -EOPNOTSUPP to pass on the FIB entry, so it'll only be installed in the
> kernel FIB.
>
> The FIB flush path is modified also to call into the swdev driver to flush the
> FIB entries from hardware.
>
> The rocker swdev driver is updated to support these new ndo ops.  Right now
> rocker only supports IPv4 singlepath routes, but follow-on patches will add
> IPv6 and ECMP support.  Also, only unicast IPv4 routes are supported, but
> follow-on patches will add multicast route support.
>
> Testing was done in my simulated network envionment using VMs and the rocker
> device.  I'm using Quagga OSPFv2 for the routing protocol for automatic control
> plane processing.  No modifications to Quagga or netlink/iproute2 is required;
> it just works.
>
> One important metric is the time spent installing/removing FIB entries from the
> kernel and the device.  With these patches applied, I measured the wall time
> required to install and remove 10K IPv4 routes.  I used ip route add cmd in
> batch mode to install static routes.  I used the ip route flush cmd to delete
> the routes.  This is 10000 routes installed to the kernel's FIB and to the
> swdev device's L3 tables.  And then removed from each.  The performance is less
> than a second for each operation.  This is on my simulated rocker device running
> on a VM, so a real embedded CPU would probably do much better.
>
> My batch has 10K lines of:
>
> simp@...p:~$ head east
> route add 16.0.0.0/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.1/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.2/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.3/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.4/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.5/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.6/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.7/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.8/32 nexthop via 11.0.0.2 dev swp1
> route add 16.0.0.9/32 nexthop via 11.0.0.2 dev swp1
> [...]
>
> Install/removing routes:
>
> simp@...p:~$ wc -l east
> 10000 east
> simp@...p:~$ ip route show root 16/8 | wc -l
> 0
> simp@...p:~$ time sudo ip --batch east
>
> real    0m0.715s
> user    0m0.092s
> sys     0m0.388s
> simp@...p:~$ ip route show root 16/8 | wc -l
> 10000
>
> [At this point, 10K routes are installed in kernel and the device]
>
> simp@...p:~$ time sudo ip route flush root 16/8
>
> real    0m0.458s
> user    0m0.000s
> sys     0m0.284s
> simp@...p:~$ ip route show root 16/8 | wc -l
> 0
>
> [All gone]
>
> Scott Feldman (3):
>   net: add IPv4 routing FIB support for swdev
>   net: call swdev fib del for flushed routes
>   rocker: implement IPv4 fib offloading
>
>  drivers/net/ethernet/rocker/rocker.c |  441 +++++++++++++++++++++++++++++++++-
>  include/linux/netdevice.h            |   22 ++
>  include/net/switchdev.h              |   18 ++
>  net/ipv4/fib_trie.c                  |   31 ++-
>  net/switchdev/switchdev.c            |   89 +++++++
>  5 files changed, 592 insertions(+), 9 deletions(-)
>
> --
> 1.7.10.4
>
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