Le 03/09/2010 17:33, George Bosilca a écrit :
>>> GM      250                 NO           Doubtful
>>>       

This one should be 2000 (assuming nobody runs Myrinet 1280 from the 90s
anymore :))

>>> MX      2000/10000          YES (Mbs)    Correct (before the patch)
>>> OFUD    800                 NO           Doubtful
>>> OpenIB  2000/4000/8000      YES (Mbs)    Correct (multiplied by the 
>>> active_width)
>>>
>>>       
>> I found the problem when using both MX and OpenIB at the same time, so
>> they can't be both wrong or both correct. IB was reporting 800, not
>> 2000/4000/8000. Maybe because auto-detect didn't work and the default is
>> wrong:
>> btl_openib_mca.c:527:    mca_btl_openib_module.super.btl_bandwidth = 800;
>>     
> It appears that Open IB only auto-detect the bandwidth if the value is 
> explicitly set to zero via the mca parameters. As a last resort: as for the 
> other devices you can set it manually. Use something like 
> btl_openib_bandwidth_%dev_name% to set the bandwidth per device.
>   

Ah thanks, it helps a lot. I added a similar mca parameter to tune the
MX/Open-MX bandwidth as well, and I can tune averything I want now.

By the way, why is IB auto-detect disabled by default?

Brice

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