[ofa-general] Ipoib child interfaces are created in dgram mode, even if the config file (and main interface) specify connected mode.

[Hal Rosenstock]

On Mon, Jun 1, 2009 at 10:01 AM, Mike Heinz <michael.heinz at qlogic.com> wrote:
> One of our testers recently reported that he was getting different
> performance numbers from IPOIB depending on whether he was using interface
> ib0 or  a child interface he had created with
> /sys/class/netib0/create_child.
>
>
>
> Investigating, I noticed that the two interfaces have different MTU sizes:
>
>
>
> ib0       Link encap:UNSPEC  HWaddr
> 80-00-00-02-FE-80-00-00-00-00-00-00-00-00-00-00
>
>           inet addr:172.21.33.58  Bcast:172.21.255.255  Mask:255.255.0.0
>
>           inet6 addr: fe80::211:7500:ff:8fa4/64 Scope:Link
>
>           UP BROADCAST RUNNING MULTICAST  MTU:65520  Metric:1
>
>           RX packets:76 errors:0 dropped:0 overruns:0 frame:0
>
>           TX packets:23147668 errors:0 dropped:0 overruns:0 carrier:0
>
>           collisions:0 txqueuelen:256
>
>           RX bytes:5284 (5.1 Kb)  TX bytes:17365044664 (16560.5 Mb)
>
>
>
> ib0.9001  Link encap:UNSPEC  HWaddr
> 80-00-00-06-FE-80-00-00-00-00-00-00-00-00-00-00
>
>           inet addr:172.21.34.58  Bcast:172.21.255.255  Mask:255.255.0.0
>
>           inet6 addr: fe80::211:7500:ff:8fa4/64 Scope:Link
>
>           UP BROADCAST RUNNING MULTICAST  MTU:2044  Metric:1
>
>           RX packets:60413619 errors:0 dropped:0 overruns:0 frame:0
>
>           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>
>           collisions:0 txqueuelen:256
>
>           RX bytes:112572449188 (107357.4 Mb)  TX bytes:0 (0.0 b)
>
>
>
>
>
> This leads me to believe that the child interface is in datagram mode even
> though the parent is in connected mode.
>
>
>
> Is this expected behavior? Is there a way to change this?

Can the child interface's mode (/sys/class/net/ib0.9001/mode) be
changed (to connected) ? See Documentation/ipoib.txt

-- Hal

> --
>
> Michael Heinz
>
> Principal Engineer, Qlogic Corporation
>
> King of Prussia, Pennsylvania
>
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