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Subject: [OMPI users] 3.5 seconds before application launches
From: Vittorio (vitto.giova_at_[hidden])
Date: 2009-02-24 19:42:21

I'm using OpenMPI 1.3 on two nodes connected with Infiniband; i'm using
Gentoo Linux x86_64.

I've noticed that before any application starts there is a variable amount
of time (around 3.5 seconds) in which the terminal just hangs with no output
and then the application starts and works well.

I imagined that there might have been some initialization routine somewhere
in the Infiniband layer or in the software stack, but as i continued my
tests i observed that this "latency" time is not present in other MPI
implementations (like mvapich2) where my application starts immediately (but
performs worse).

Is my MPI configuration/installation broken or is this expected behaviour?
thanks a lot!