[dpdk-dev] Question on documentation / Mellanox ConnectX-3

Marcelo Ricardo Leitner marcelo.leitner at gmail.com
Sun Apr 8 23:27:50 CEST 2018


On Thu, Apr 05, 2018 at 11:26:21AM +0200, Adrien Mazarguil wrote:
> On Tue, Apr 03, 2018 at 02:59:38PM -0300, Marcelo Ricardo Leitner wrote:
> > Hi,
> >
> > http://docs.openvswitch.org/en/latest/howto/dpdk/ says:
> >
> > Some NICs (i.e. Mellanox ConnectX-3) have only one PCI address
> > associated with multiple ports. Using a PCI device like above won’t
> > work. Instead, below usage is suggested:
> >
> > $ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
> >     options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55:01"
> > $ ovs-vsctl add-port br0 dpdk-p1 -- set Interface dpdk-p1 type=dpdk \
> >     options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55:02"
> >
> > But these MACs are 7 bytes long. Seems the idea was to mention the two
> > incremental MAC addresses that the ports have, and thus the ':55'
> > should have been removed from there, right?
> >
> > Reading the code, it doesn't seem prepared to handle the extra byte in
> > any (special) way.
>
> After a quick glance at the original patch [1], I confirm it looks like a
> mistake in the OVS documentation. MAC addresses should be 6 bytes long, the
> 7th byte is not a workaround to identify a physical port like I initially
> thought.
>
> As you pointed out, since default MAC addresses on mlx4 ports are normally
> incremental, documentation should read something like:
>
>  $ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
>      options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55"
>  $ ovs-vsctl add-port br0 dpdk-p1 -- set Interface dpdk-p1 type=dpdk \
>      options:dpdk-devargs="class=eth,mac=00:11:22:33:44:56"
>
> [1] https://github.com/openvswitch/ovs/commit/5e7588186839

Thanks Adrien. Question now is, who can fix the doc?

  Marcelo


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