[MITgcm-devel] linux_amd64_ifort+mpi_ice_nas update

[Jean-Michel Campin]

Hi Dimitris,

I would vote for the conservative approach, to just change 
NOOPTFLAGS to '-O1 -fp-model precise'
and keep seaice_growth.F in the NOOPTFILES list.
We don't need -fPIC twice (in FFLAGS and NOOPTFLAGS), so no need 
to keep it in NOOPTFLAGS setting.

Just to finish with few tests with ifort (v13) on acesgrid:
a) As I mentionned earlier, with -fast (see e.g.:
http://mitgcm.org/testing/results/2013_10/tr_acesgrid-ifc_20131020_0/summary.txt
) there are few "FAIL" with low level of agreement and, in addition,
the restart test fails for all the cubed-sphere and many Non-hydrostatic 
experiments:
http://mitgcm.org/testing/results/2013_10/rs_acesgrid-ifc_20131020_0/summary.txt

b) It get better if I change from -O2 to -O1, but still most of 
the cubed-sphere restart tests fail.

c) If I jsut set: FOPTIM="-O1 -align -ip -fp-model precise -xHost"
then the testreport output + the restart are all good, and identical 
to the default (-ieee) results.

d) by putting back -O2 so that:
 FOPTIM="-O2 -align -ip -fp-model precise -xHost"
all the restart tests pass, little changes in testreport output 
compared to (c) except for global_with_exf.yearly (fail @ 6)
and few little changes in lab_sea & seaice_obcs (but for 
lab_sea.salt_plume and seaice_obcs the agreement with ref output 
is even better than it was in (c)).

e) finally, replacing "-fp-model precise" with "-fp-model source"
does not change anything.

And since I think it's better to have working restart, I think I will 
change the optfile "linux_amd64_ifort11" to what I tried in (d).
The problem with global_with_exf.yearly might be related to a wrong
compiler optimisation (vectorisation type) of one source file; 
but it takes time to figure out which one, and this might depend on 
the compiler & mpi version.

Cheers,
Jean-Michel

On Mon, Oct 21, 2013 at 05:37:55PM +0000, Menemenlis, Dimitris (3248) wrote:
> David thanks for testing.  So what next?
> We switch to "NOOPTFLAGS='-O1 -fPIC'" and let folks give try it in bigger configs?
> Or do we try to push for even more aggressive optimization?
> 
> Dimitris Menemenlis
> 
> On Oct 21, 2013, at 10:32 AM, David Ferreira wrote:
> 
> > Jean-Michel, Dimitris,
> > The testreports of global_ocean.cs32x15, lab_sea, offline_exf_seaice, seaice_itd, and seaice_obcs with NOOPTFLAGS=-O1 (with -noieee) give the same results as with -O0.
> > So nothing special at this level.
> > david
> 
> 
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