Dual core performance estimate

[Gideon Simpson]

I asked the original question, and I have a follow up.  Like it or  
not, multi-core CPUs have been thrust upon us by the manufacturers  
and many of us are more likely to have access to a shared memory,  
multi core/multi processor machine, than a properly built cluster  
with MPI in mind.

So, two questions in this direction:

1.  How feasible would it be to implement  OpenMP in PETSc so that  
multi core CPUs could be properly used?

2.  Even if we are building a cluster, it looks like AMD/Intel are  
thrusting multi core up on is.  To that end, what is the feasibility  
of merging MPI and OpenMP so that between nodes, we use MPI, but  
within each node, OpenMP is used to take advantage of the multiple  
cores.

-gideon

On Nov 18, 2007, at 3:53 PM, Aron Ahmadia wrote:

> Hi Ben,
>
> You're asking a question that is very specific to the program you're
> running.  I think the general consensus on this list has been that for
> the more common uses of PETSc, getting dual-cores will not speed up
> your performance as much as dual-processors.  For OS X, dual-cores are
> pretty much the baseline now, so I wouldn't worry too much about it.
>
> ~A
>
> On Nov 18, 2007 3:34 PM, Ben Tay <zonexo at gmail.com> wrote:
>> Hi,
>>
>> someone was talking abt core 2 duo performance on os x in some  
>> previous
>> email. it seems that due to memory issues, it's not possible to  
>> get 2x the
>> performance. there's also some mention of amd vs intel dual core.
>>
>> for computation using PETSc, is there any reason to buy one  
>> instead of the
>> other? Also, supposed I use winxp + mpich2 + PETSc on a dual core,  
>> what sort
>> of performance increase can we expect as compared to PETSc + nompi  
>> on the
>> same machine?
>>
>> or is that too difficult an answer to give since there are too  
>> many factors?
>>
>> thank you
>>
>> regards
>

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