[Users] Cactus -- Bench_Whisky_Carpet benchmark

[Erik Schnetter]

On Apr 4, 2008, at 05:28:01, Baker D.J. wrote:
> Hi all,
>
> Hopefully this is very easy question for someone.
>
> My knowledge of Cactus is minimal. I'm not a user of the package,  
> however I am involved in preparing some applications for  
> benchmarking. I've recently been testing out Bench_Whisky_Carpet  
> since this benchmark most closely represents the type of Cactus  
> applications that researchers at Southampton are running. On our  
> latest Opteron (3 GHz) processors it's taking in the region of 11  
> minutes to complete, and my major concern is that is will complete  
> even faster as we move to other systems (perhaps..). We have some  
> Intel quad core machines arriving soon, and that will be an  
> interesting test case.
>
> My question is essentially how to "rebase" this benchmark without  
> actually losing the essence of what it's doing. That is, is there a  
> parameter that I can adjust to increase the number of iterations  
> completed or whatever?
>
> Please could some one advise me.


David,

the benchmarks were designed with two goals in mind: the amount of  
memory per core should be between 500 MB and 1000 GB, and it should  
finish in between 10 to 15 minutes.  Both can be adapted.  (In fact,  
there are even two benchmarks on the web page with different memory  
requirements.)

The parameters global_nx, global_ny, and global_nz define how much  
memory is used.  The parameter cctk_itlast defines how long it runs --  
it sets the number of iterations.  Obviously, if you change memory  
usage, the time is going to change proportionally as well.  Due to the  
AMR algorithm, it is "nice" to keep cctk_itlast at a small integer  
multiple of a power of two, but this is not a requirement.

We are currently updating the benchmarks, including using a new and  
more efficient version of the underlying mesh refinement driver.  We  
have finalised some vacuum benchmarks and are currently working on  
updating the hydrodynamics benchmark.  I suggest to not use the  
current benchmark for large (>100) number of processors.  If you are  
interested, we can give you access to an early version of the new  
benchmark.

Good luck,
-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/

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