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Re: Possible explaination why large_real_kind_form_io_2.f90 is failing on PPC/OSX
- From: dominiq at lps dot ens dot fr (Dominique Dhumieres)
- To: dominiq at lps dot ens dot fr, tprince at myrealbox dot com
- Cc: fortran at gcc dot gnu dot org, schnetter at cct dot lsu dot edu
- Date: Sun, 14 Jan 2007 23:59:08 +0100 (CET)
- Subject: Re: Possible explaination why large_real_kind_form_io_2.f90 is failing on PPC/OSX
> the compiler will assure that real(10) doesn't straddle cache line boundaries,
This assumes that you are using mostly data from the cache, when you have codes
like mines that sweep large arrays at each iteration, they have to read and wrote
at each iteration so going from 10 bytes to 16 almost double the memory bandwith
which is the main bottleneck for my codes (not enough FP per node). So it is quite
unlikely that I'll use real(110) (or 16) in my applications, only for tests
(when I really need high precision, it happened once in my life, I use Mathematica).
Dominique