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Subject: Re: [OMPI users] Blocking communication a thread better thenasynchronous progress?
From: tomek (t.koziara_at_[hidden])
Date: 2009-08-21 12:24:12


>
>> Is doing blocking communication in a separate thread better then
>> asynchronous progress?
>> (At least as a workaround until the proper implementation gets
>> improved)
>>
>
>
> At the moment, yes. OMPI's asynchronous progress is "loosely
> tested" (at best).
>
> OMPI's threading support is somewhat stable for some devices (e.g.,
> not OpenFabrics-based networks), but it's still somewhat new, so
> feedback would be welcome here.

I quickly modified my asynchronous code (Isend - Recv) to have a
pthread doing Irecv - Rsend for point to point collective
communication (which normally works fine for me). But still - on my
wee laptop - the thread / blocking comm. combination is quite slow. I
will play around with it to see whether it can be improved. Of course,
laptop is not a good device for a very conclusive testing, but if
things are too slow here, I wouldn't expect them to work great
elsewhere.

I wonder whether the OMPI 1.3 on OS X Leopard will have MPI threads
enabled (the 1.2.8 version on Darwin doesn't)...