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Re: 20040220: Netcdf optimizations for NEC's SX systems

>To: address@hidden
>cc: address@hidden,
>cc: address@hidden
>From: Dave Parks <address@hidden>
>Subject: Netcdf optimizations for NEC's SX systems
>Organization: ?
>Keywords: 200402202021.i1KKLLrV019559 netCDF NEC SX

Hi David,

> I'm not sure how to get this incoporated in to your offical release, but
> thought that we should pass this along ....
> 
> 
> We have made a trivial change to source file 'putget.c' in directory libsrc
> of the netcdf distribution.
> 
> When building for the NEC SX architecture, we now define NFILL (line 52) to
> be 2048.
> 
> So we have:
> 
> #if   _SX
> #define       NFILL   2048
> #else
> #define       NFILL   16
> #endif
> 
> 
> While generating a 50GB data file, we have observed a decrease of
> ~360 CPU seconds on an SX-6 processor.

Thanks for passing this along.  I've added it to our version 3.6.0
development branch, so it should be in the next release.  I changed
putget.m4 rather than putget.c, since the latter is generated from the
former. 

--Russ

_____________________________________________________________________

Russ Rew                                         UCAR Unidata Program
address@hidden          http://www.unidata.ucar.edu/staff/russ