***SPAM*** Re: [ofa-general] 4K MTU with OpenSM?

[Hal Rosenstock]

On Wed, Mar 18, 2009 at 5:44 AM, Sasha Khapyorsky <sashak at voltaire.com> wrote:
> On 18:17 Tue 17 Mar     , Dave Olson wrote:
>> On Tue, 17 Mar 2009, Hal Rosenstock wrote:
>> | On Tue, Mar 17, 2009 at 3:02 PM, Ted H. Kim <Ted.Kim at sun.com> wrote:
>> | > Is there way to config 4K IB MTU with OpenSM?
>> | > What's the option of file setting for that?
>> |
>> | See the partition configuration section in the man page or
>> | opensm/doc/partition-config.txt. It's something like:
>> |
>> | Default=0x7fff,ipoib,mtu=5:ALL=full;
>
> This will use this MTU value for IPoIB multicast group.
>
> As far as I understood Ted's question was "how to setup port's MTU using
> OpenSM". Assuming so I don't think that OpenSM has such functionality
> now (although it should not be very hard to add).

Do you mean admin the port's MTU ? If so, why would there be such a need ?

The only time it might be needed would be to select a lower MTU than
the peers support. That was done for Tavor for a performance issue. Do
you envision some other need ?

-- Hal

> Sasha