[mpich2-dev] wrapping library calls

[chan at mcs.anl.gov]

Both comm/bin and comm/fast/bin have mpich2version in V1R3 and V1R4.
comm/fast/bin/mpich2version shows that it was compiled with "-O2 -O4"
(Brian, you may want to add --disable-fast when building the comm/fast/bin
versin to get rid of the confusing -O2), the resulting libraries seems
to be compiled with -O4 which might have been too aggressive ?

A.Chan

----- "Rob Latham" <robl at mcs.anl.gov> wrote:

> On Tue, Nov 24, 2009 at 06:17:33AM -0600, Brian Smith wrote:
> 
> > The libraries in comm/fast are compiled using the XL compilers with
> 
> > minimal asserts and a lot of debug turned off. They tend to make a 
> > reasonable improvement for point-to-point operations and not much of
> an 
> > improvement for collectives. We generally recommend you make sure
> your app 
> > runs fine using the comm/bin scripts first, then, yes, for benchmark
> 
> > results you can recompile against the comm/fast libraries.
> 
> At least in V1R3, I/O codes using the fast libraries often abort.
> Kazutomo tells me it's related to something involving alignment of
> floating point accesses?   I should try again with V1R4.
> 
> ==rob
> 
> -- 
> Rob Latham
> Mathematics and Computer Science Division
> Argonne National Lab, IL USA