Performance improvement in netCDF 3.5.1-beta12

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: Performance improvement in netCDF 3.5.1-beta12
• From: Russ Rew <russ@xxxxxxxxxxxxxxxx>
• Date: Fri, 08 Aug 2003 14:06:21 -0600

Hi,

We don't usually announce new beta releases of netCDF, but the latest
release, version 3.5.1-beta12, fixes a significant performance
problem.  We owe thanks to Matt Huddleston, Mathis Rosenhauer, and
Gottfried Necker, who first reported and helped diagnose the problem
on NEC SX6 platforms and then helped test the fixed version.

The problem, which is not platform-specific, caused extra I/O as if
unnecessary nc_sync() calls were being made.  Data would be read and
written correctly, but buffers would be flushed unnecessarily.  The
problem was first introduced in version 3.5.0, but it became
significantly worse in 3.5.1-beta10 as the result of another change.

If you installed version 3.5.1-beta10 and noticed slow downs, or if
netCDF I/O seems to be a bottleneck in your application, you might
want to try the new beta release:

  ftp://ftp.unidata.ucar.edu/pub/netcdf/netcdf-beta.tar.Z

As usual, please report problems to support@xxxxxxxxxxxxxxxx.

--Russ Rew

_____________________________________________________________________

Russ Rew                                         UCAR Unidata Program
russ@xxxxxxxxxxxxxxxx                      http://my.unidata.ucar.edu