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Subject: Re: [OMPI users] Loopback Communication
From: Giovanni Davide Vergine (verginegiovanni_at_[hidden])
Date: 2008-03-01 07:57:54


Loopback communication it's shared memory copy, of course.
Even if it would be implemented with socket() and other network
syscalls, kernel will do finally only memory copying.

Il giorno 01/mar/08, alle ore 00:25, Elvedin Trnjanin ha scritto:

> I'm using a "ping pong" program to approximate bandwidth and latency
> of
> various messages sizes and I notice when doing various transfers (eg.
> async) that the maximum bandwidth isn't the system's maximum
> bandwidth.
> I've looked through the FAQ and I haven't noticed this being covered
> but
> how does OpenMPI handle loopback communication? Is it still over a
> network interconnect or some sort of shared memory copy?
>
> - Elvedin
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