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.
--
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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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