Re: [AMBER-Developers] questions about compiler flags

From: Mengjuei Hsieh <>
Date: Tue, 2 Feb 2010 01:40:09 -0800

On Mon, Feb 01, 2010 at 03:18:40PM -0500, case wrote:
> Two compiler options questions:
[libc issues deleted]
> 2. Do we really need the "-ip -O3 -xHost" flags for optimized ifort compiles?
> Is this better/worse/the same as "-fast" (used for pmemd)? Does sander need
> anything more than -O3? Is there a good compromise between "fastest of all
> 2^N possible combinations of flags on this particular machine" and "something
> that sacrifices a few percent in performance but which is likely to both work
> now and continue working after Intel puts out its next release"?

IIRC, "-ip" doesn't really optimized the speed too much although it
does theoretically reduce program loading time. As to -xHost, isn't
it for replacing SSE1/2/3 ? I like SSE* arguments, but I am not sure
if that gives you dramatic performance boost.

If performance is really a concern for certain programs, how about
we release some well-optimized executables for them on some major

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Received on Tue Feb 02 2010 - 02:00:02 PST
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