Does the recompile switch on netcdf4 features, or is it still writing a classic
nc3 file using the nc4 libs? Just to clarify -- Not that I know if that makes
a difference.
-- Ted
On Jan 18, 2012, at 2:10 AM, Karsten Bolding wrote:
> Hello
>
> I'm working on a 1D ocean model that stores its output in NetCDF.
>
> With NetCDF4 I've experienced some performance issues as shown in the
> timings below for a specific model run:
>
> NetCDF4:
> real 0m42.940s
> user 0m3.630s
> sys 0m0.110s
>
> NetCDF 3.6.3:
> real 0m1.838s
> user 0m1.820s
> sys 0m0.000s
>
> Its run on the same system only recompiling the executable to link
> either NetCDF 3 or 4.
>
> Disk performance is not an issue:
> /dev/sda:
> Timing buffered disk reads: 344 MB in 3.02 seconds = 114.06 MB/sec
>
> as the resulting file is only 10MB.
>
> I'm using the 4.2 release candidate configured as follows:
>
> C:
> CPPFLAGS=-I/opt/hdf5/include LDFLAGS=-L/opt/hdf5/lib ./configure
> --prefix=/opt/netcdf-${netcdf_ver}_IFORT
>
> Fortran:
> FFLAGS="-O3" FC=ifort F77=ifort CPPFLAGS=-I/opt/hdf5/include CFLAGS="-O3"
> LDFLAG S=-L/opt/hdf5/lib ./configure --prefix=/opt/netcdf-${netcdf_ver}_IFORT
>
> i.e. no specific optimisation.
>
> Netcdf 3.6.3 is also compiled without specific optimisation.
>
> Any ideas anyone?
>
> Karsten
>
> PS: I've done the above simulations a number of times with consistent
> results.
>
>
> --
> ----------------------------------------------------------------------
> Karsten Bolding Bolding & Burchard ApS
> Strandgyden 25 Phone: +45 64422058
> DK-5466 Asperup Fax: +45 64422068
> Denmark Email: karsten@xxxxxxxxxxxxxxxxxxxx
>
> http://www.findvej.dk/Strandgyden25,5466,11,3
>
> Q: What is irony?
> A: Almost the same as goldy and bronzy - just made of iron ...
> (from Blackadder)
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