[gmx-users] Re : Gromacs-3.3: release candidate 1 available!

Erik Lindahl lindahl at sbc.su.se
Thu Sep 8 18:23:35 CEST 2005


Hi Michel,

The retuned loops are for x86-64; I've rescheduled them to use all  
available registers (16, iso 8 for ia32).

There are no improvements to the ia64 loops that I know of; the  
limitation on host ia64 hosts seems to be the cache and the compilers  
ability to optimize the C neighborsearching code.

For small systems (neighborlists fit in cache) the ia64 nonbonded  
loops execute very close to machine peak. The only reason why x86-64  
and ia32 are faster is that they provide SIMD instructions.

Cheers,

Erik


On Sep 8, 2005, at 4:03 PM, Michel Cuendet wrote:

> Hi Erik,
>
>
>> And, just to give you some incitement for testing: Release 3.3 has
>> ... x86-64 and EM64T 64-bit
>> assembly loops (recently re-tuned to use all register), ...
>>
>>
> Have these "recently re-tuned loops" been added after 27.05.2005 ?
>
> If yes, would they improve substantially the speed on itaniums ?
>
> Thanks,
>
> Michel
>
> -- 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> Michel Cuendet, Ph.D. student
> Laboratory of Computational Biochemistry and Chemistry
> Swiss Federal Institute of Technology in Lausanne (EPFL)
> CH-1015 Lausanne
> Switzerland                            Phone : +41 21 693 0324
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