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Subject: Re: [OMPI users] OpenIB problems
From: Andrew Friedley (afriedle_at_[hidden])
Date: 2007-11-27 16:19:33


Brock Palen wrote:
>>> What would be a place to look? Should this just be default then for
>>> OMPI? ompi_info shows the default as 10 seconds? Is that right
>>> 'seconds' ?
>> The other IB guys can probably answer better than I can -- I'm not an
>> expert in this part of IB (or really any part I guess :). Not sure
>> why
>> a larger value isn't the default. No, its not seconds -- check the
>> description of the MCA parameter:
>>
>> 4.096 microseconds * (2^btl_openib_ib_timeout)
>
> You sure?
> ompi_info --param btl openib
>
> MCA btl: parameter "btl_openib_ib_timeout" (current value: "10")
> InfiniBand transmit timeout, in seconds
> (must be >= 1)

Yeah:

MCA btl: parameter "btl_openib_ib_timeout" (current value: "10")
          InfiniBand transmit timeout, plugged into formula:
          4.096 microseconds * (2^btl_openib_ib_timeout)(must be
>= 0 and <= 31)

Reading earlier in the thread you said OMPI v1.2.0, I got this from a
trunk checkout thats around 3 weeks old. A quick check shows this
description was changed between 1.2.0 and 1.2.1. However the use of
this parameter hasn't changed -- it's simply passed along to IB verbs
when creating a queue pair (aka a connection).

Andrew