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Subject: Re: [OMPI users] BTL question
From: Teige, Scott W (steige_at_[hidden])
Date: 2008-12-26 04:35:31


Quoting "Pavel Shamis (Pasha)" <pashash_at_[hidden]>:

> Teige, Scott W wrote:
>> Greetings,
>>
>> I have observed strange behavior with an application running with
>> OpenMPI 1.2.8, OFED 1.2. The application runs in two "modes", fast
>> and slow. The exectution time is either within one second of 108 sec.
>> or within one second of 67 sec. My cluster has 1 Gig ethernet and
>> DDR Infiniband so the byte transport layer is a prime suspect.
>>
>> So, is there a way to determine (from my application code) which
>> BTL is really being used?
I've done this...
> You may specify:
> --mca btl openib,sm,self
Application sometime runs fast, sometimes runs slow
> And OpenMPI will use IB and shared memory for communication.
> --mca btl tcp,sm,self
Allpication always runs fast. So...
is there a way to determine (from my application code) which
BTL is really being used?

I appreciate any help I can get,
S.

> And OpenMPI will use TCP and shared memory for communication.
>
> Thanks,
> Pasha
>
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