[Beowulf] Peformance penalty when using 128-bit reals on AMD64
Nifty Tom Mitchell
niftyompi at niftyegg.com
Fri Jun 25 08:54:24 PDT 2010
On Fri, Jun 25, 2010 at 10:28:15AM -0400, Prentice Bisbal wrote:
> One of my Fortran programmers had to increase the precision of his
> program so he switched from REAL*8 to REAL*16 which changes the size of
> his variables from 64 bits to 128 bits. The program now takes 32x longer
> to run.
I am surprised that it works as support in things like
the math lib, log and trig functions could be missing.
Which compiler is he using?
T o m M i t c h e l l
Found me a new hat, now what?
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