initial timings

[Rob Ross]

Excellent.  Now we just need to get the last big Fortran related issues 
knocked out for you...

Rob

On Fri, 22 Aug 2003, John Tannahill wrote:

> Some initial timing results for parallel netCDF =>
> 
> File size:  216 MB
> Processors:  16 (5x3+1; lonxlat+master)
> Platform:   NERSC IBM-SP (seaborg)
> 2D domain decomposition (lon/lat)
> 600x600x150 (lonxlatxlev)
> real*4 array for I/O
> Fortran code
> 
> Method 1:  Use serial netCDF.
>             Slaves all read their own data.
>             For output:
>               Slaves send their data to the Master (MPI)
>                 (all at once, no buffering; so file size restricted)
>               Master collects and outputs the data
>                 (all at once)
> 
> Method 2:  Use ANL's parallel-netcdf, beta version 0.8.9.
>             Slaves all read their own data, but use parallel-netcdf calls.
>             For output:
>               Slaves all output their own data
>                 (all at once)
> 
> Read results =>
> 
>    Method 2 appears to be about 33% faster than Method 1.
> 
> Write results =>
> 
>    Method 2 appears to be about 6-7 times faster than Method 1.
> 
> Note that these preliminary results are based on the parameters given
> above.  Next week, I hope to look at different machines, different
> file sizes (although I am memory limited on the Master as to how big
> I can go), different numbers of processors, etc.
> 
> Anyway, things look promising.
> 
> Regards,
> John
> 
> -- 
> ============================
> John R. Tannahill
> Lawrence Livermore Nat. Lab.
> P.O. Box 808, M/S L-103
> Livermore, CA  94551
> 925-423-3514
> Fax:  925-423-4908
> ============================
> 
>