Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

From: Michael Galloway (mgx_at_[hidden])
Date: 2006-12-15 07:53:42

On Thu, Dec 14, 2006 at 03:28:25PM -0700, Brian W. Barrett wrote:
> It appears that this is being caused by a problem much earlier in the
> configure process. For some reason I don't totally understand, the
> configure script is finding the size of shorts, ints, longs, long
> longs, void *s, etc. to be 2. This is rather unexpected on a 64-bit
> machine, obviously. In testing with PGI 6.1-3 on x86_64, it looks
> like the IPA option is causing this to occur -- if I remove the IPA
> option from the flags, configure runs properly.
> In my (somewhat humble) opinion, turning on such aggressive options
> is dangerous when compiling Open MPI (or most MPI implementations).
> With share memory and RDMA interconnects, assumptions compiler
> writers make when running at such high optimization setting are
> frequently not true for codes like Open MPI. And the performance
> gain in compiling the MPI layer with such high optimizations is
> frequently near zero (that being said, there is a significant
> advantage to adding some optimization flags and not including
> debugging symbols in the MPI library if you don't need them).
> It should be safe to compile Open MPI without the IPA options and
> still use IPA when compiling your application.

brian, indeed that seems to have been the issue. thanks for the help!

-- michael