[MITgcm-devel] new r4 SingleCpuIO efficiency

[Jean-Michel Campin]

Hi Dimitris,

On Fri, May 22, 2009 at 09:25:34AM -0700, Dimitris Menemenlis wrote:
> Jean-Michel, what is status of switch-over to new exchange topology?
> Do I still use the old w2_e2setup.F/W2_EXCH2_TOPOLOGY.h
> routines or do I need to update to the new stuff.

If you are not using blank-tiles, then you just need to remove
 our local copy of w2_e2setup.F & W2_EXCH2_TOPOLOGY.h
With blank-tiles, you remove also thoses 2 files but you need
 a "data.exch2" parameter file (with the list of blank-tiles), 
 and could find one example (with blank-tiles) here:
 MITgcm/verification/adjustment.cs-32x32x1/input/data.exch2.mpi
(the .mpi suffix is just there for MPI testing purpose).
If this does not work, you should complain.

Cheers,
Jean-Michel
>
> Look forward to giving the r4 IO a try.  IO is biggest bottleneck
> both for forward as well as for adjoint integrations.
>
> D.
>
> On May 22, 2009, at 7:51 AM, Jean-Michel Campin wrote:
>
>> Hi Dimitris,
>>
>> If by chance you have time to check with a short run
>> how the new version of SingleCpuIO is doing on cs-510
>> (well, given the bug I put & remove only yesterday, I guess
>> you did not try yet), I would be curious to know if you
>> can see a speed up with large amount of r4 io (compared to
>> checkpoint61m). The volume of MPI send/receive for r4 io
>> has been reduced by 2 (was r8 before) and this might speed up
>> a little the run. And if something goes wrong, let me know.
>>
>> Thanks,
>> Jean-Michel
>
> Dimitris Menemenlis <menemenlis at jpl.nasa.gov>
> Jet Propulsion Lab, California Institute of Technology
> MS 300-323, 4800 Oak Grove Dr, Pasadena CA 91109-8099, USA
> tel: 818-354-1656;  cell: 818-625-6498;  fax: 818-393-6720
>
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