[openib-general] Bug in IBMgtSim?

[Eitan Zahavi]

Hi Sven,

Yes this is the behavior of the simulator.
Any MAD leaving from a node and target to the same node also appears 
back at the sender input.
This is also the behavior of the gen1 IB stack. As you pointed out the 
SM (osm vendor layer) is
capable of dropping these duplicated MADs.

The "bug" stems from the fact the MADs when injected into the simulator 
do not carry any information about the
client which injected them. So when they finally arrive to the 
destination they are being forwarded to all "MAD
processors" attached to that node (to the specific "management class"). 
So if the SM is registered as "MAD Processor"
for SMPs on node A and sends SMP to node A the SMP will be received on 
the SM as well as on any other "MAD Processor"
attached to that node (e.g. the SMA on the node A).

Eitan

Sven-Arne Reinemo wrote:
> Hi,
>
> There seemed to be a bug in IBMgtSim where it forwards packets received
> from the SM back onto the port where the SM is connected. OpenSM just
> drops the packet so it does not seem very problematic, but I am just
> checking to see if anyone else see this behaviour. Below are an example
> from the log files.
>   
> Packet dropped by OpenSM:
>
> Dec 15 15:21:34 992520 [B44E3BB0] -> Duplicate TID 0x6A7B00001234
> received (not a response). Dropping the MAD.
>
>
> Packets forwarded to the SM (the first one is the one that is dropped):
>
> -I- Using random seed:96960
> -I- Parsing topology definition:/simulator/scalability/test_top.topo
> -I- Defined 3/3 systems/nodes
> -I- Init fabric: fabric:1
> -I- Started server: opensm.simula.no port:60493
> -I- Ready to serve
> -I- Connecting: sock9 127.0.1.1 48227
> --------------------------------------------------------
>   sl                       0x0
>   pkey_index               0x0
>   slid                     0x0
>   dlid                     0xffff
>   sqpn                     0x0
>   dqpn                     0x0
> --------------------------------------------------------
> --------------------------------------------------------
>   base_ver                 0x1
>   mgmt_class               0x81
>   class_ver                0x1
>   method                   0x1
>   status                   0x0
>   class_spec               0x100
>   trans_id                 0x00006a7b00001234
>   attr_id                  0x11
>   attr_mod                 0x0
> --------------------------------------------------------
> --------------------------------------------------------
>   sl                       0x0
>   pkey_index               0x0
>   slid                     0xffff
>   dlid                     0x0
>   sqpn                     0x0
>   dqpn                     0x0
> --------------------------------------------------------
> --------------------------------------------------------
>   base_ver                 0x1
>   mgmt_class               0x81
>   class_ver                0x1
>   method                   0x81
>   status                   0x8000
>   class_spec               0x0
>   trans_id                 0x00006a7b00001234
>   attr_id                  0x11
>   attr_mod                 0x0
> --------------------------------------------------------
>
>
>