Fortran compilers for Linux/mpich

David van der Spoel spoel at xray.bmc.uu.se
Sun Nov 25 09:53:58 PST 2001


On Sun, 25 Nov 2001, Robert G. Brown wrote:

>Do you have any idea what the overall marginal benefit is of using your
>hand-optimized routines when working on large datasets (too big to fit
>into cache)?  In particular, does performance devolve to
>memory-bandwidth-bound behavior (and hence end up being the same for
>MILC and SSE and dominated by the memory bus speed)?
>
>    rgb
Of course YMMV, but for our application (molecular dynamics) the impact of
SSE is high: a factor of 1.5 for large applications, more than so for
smaller applications (see http://www.gromacs.org/benchmarks/scaling.php
for comparisons). I should admit that it was very time consuming to write
all that much assembly code (but the guy did it out of his own free will)


Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://zorn.bmc.uu.se/~spoel
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