[openib-general] ip_ib_mc_map?

[Or Gerlitz]

Or Gerlitz wrote:
> On 2/2/07, Doug Ledford <dledford at redhat.com> wrote:
>> Yeah, I've got a setup, I just don't have any multicast tests that I
>> run.  Any test programs you have for multicast in particular would be
>> helpful.

> This is farely simple to do: have some multicast traffic routed over
> an IPoIB subnet on two nodes, eg using
> 
> $ route add -net 224.0.0.0 netmask 255.0.0.0 dev ib0
> $ iperf -usB 224.5.5.5 -i 1

OK, to verifying the problem is away based on running client/server is 
actually harder, since when the problem persist data is being moved on 
the broadcast group... so basically, first thing you want to do is set 
routing, then open an iperf server and see if the netstack has computed 
a correct IPoIB multicast hw address and instructed the device to use it.

> # iperf -usB 224.5.5.5 &

this is on U3, the stack computed fine the hw addresses for 224.5.5.5 
and 224.0.0.1

> # ip maddr show ib0
> 5:      ib0
>         link  00:ff:ff:ff:ff:12:40:1b:00:00:00:00:00:00:00:00:00:05:05:05
>         link  00:ff:ff:ff:ff:12:40:1b:00:00:00:00:00:00:00:00:00:00:00:01
>         inet  224.5.5.5
>         inet  224.0.0.1

this is on U4, the stack did not compute any hw addresses for 224.5.5.5 
and 224.0.0.1, the inet addresses are the output of /proc/net/igmp which 
means the stack is aware this node joins these groups but as we know the 
ARPHRD_INFINIBAND case was removed from the code computing a multicast 
link layer address...

> # ip maddr show ib0
> 8:      ib0
>         inet  224.5.5.5
>         inet  224.0.0.1

So basically, if on your U5-staged node, you have the same
# ip maddr show output as over U3 we made a progress. Really verifying 
that this traffic does not go over the broadcast group is a little bit 
harder, you would need a third active IPoIB device (that is another node 
or a second ipoib running device on the rx machine - eg ib1), run the 
iperf multicast test and make sure the --rx counters-- of the third 
device doe not get progress, where on U3 they would progress since all 
mcast traffic goes on the broadcast channel.

Please let me know if you need any further clarifications on how to test 
this, and... thanks! for taking care of it.

Or.