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Subject: Re: [OMPI devel] IBCM error
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-07-15 07:44:21


On Jul 15, 2008, at 7:30 AM, Ralph Castain wrote:

>> Minor clarification: we did not test RDMACM on RoadRunner.
>
> Just for further clarification - I did, and it wasn't a particularly
> good
> experience. Encountered several problems, none of them overwhelming,
> hence
> my comments.

Ah -- I didn't know this. What went wrong? We need to fix it if
there are problems.

>> RDMACM, on the other hand, is *necessary* for iWARP connections. We
>> know it won't scale well because of ARP issues, to which the iWARP
>> vendors are publishing their own solutions (pre-populating ARP
>> caches,
>> etc.). Even when built and installed, RDMACM will not be used by
>> default for IB hardware (you have to specifically ask for it). Since
>> it's necessary for iWARP, I think we need to build and install it by
>> default. Most importantly: production IB users won't be disturbed.
>
> If it is necessary for iWARP, then fine - so long as it is only used
> if
> specifically requested.
>
> However, I would also ask that we be able to -not- build it upon
> request so
> we can be certain a user doesn't attempt to use it by mistake ("gee,
> that
> looks interesting - let Mikey try it!"). Ditto for ibcm support.

Pasha added configure switches for this about a week ago:

     --en|disable-openib-ibcm
     --en|disable-openib-rdmacm

-- 
Jeff Squyres
Cisco Systems