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Subject: Re: [hwloc-users] Patch to disable GCC __builtin_ operations
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-06-08 17:40:49


On Jun 8, 2011, at 5:30 PM, Dave Goodell wrote:

>> Is there a reason we wouldn't disable it in OMPI's hwloc by default?
>
> Performance will be better when left enabled on platforms where the compiler and the architecture are in agreement...

I'm not too concerned about hwloc's performance in OMPI -- it'll be used during initialization only. Unless there's a dramatic difference for, say, large-core-count machines, I'd be inclined to just disable it unless there's some reason to leave it on. It's one less thing that a user will have to know/remember to --disable, even in Josh's exotic case.

> IMO Josh's use case is a bit exotic. He's using one system's compiler as an approximation of an appropriate compiler for another system instead of using a cross compiler or compiling in an identical environment. That viewpoint may or may not be shared by the OMPI developers.
>
> -Dave
>
>
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-- 
Jeff Squyres
jsquyres_at_[hidden]
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