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Subject: Re: [OMPI users] openMPI installation on front-end and worker nodes
From: Reuti (reuti_at_[hidden])
Date: 2012-02-22 08:39:39


Hi,

Am 22.02.2012 um 14:21 schrieb Salvatore Podda:

> we have a computational infrastructure composed from front end and worker nodes
> which differ slightly differ in the architectures on board (I mean same processor different socket).

can you clarify this - something like an AM3 CPU in an AM3+ socket?

> OFED and openMPI have been compiled and built on both systems at the same version level.
> As users have access to the system only through front-end nodes (they compile on front-end
> and submit job to worker nodes) the eventual difference in the OFED/openMPI installation
> depending from the architecture can jeopardize the operation and the performance of the
> user application?
>
> More generally, in the case of a front-end nodes with a processors definitively different from
> worker nodes (same firm i.e.Intel) can openMPI applications compiled on one run correctly
> on the others?

This depends on the used compiler options. If you compile just for a CPU type in the machine you compile on (and usually this is taken as the target architecture by the compiler), it might fail on older CPUs which are in the nodes. Like compiling on a machine with Shanghai-64 CPU might fail on older Opterons, unless you use compiler switches to target the least common instruction.

-- Reuti

> Many thanks
>
> Salvatore
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