Jason, Levi,
thanks for your comments. So it's 1 core per 1 GPU.
And yes, I know that currently Amber11 only supports single GPU
simulations. For now, I'm just thinking about a (cost-effective) system
to run several of them concurrently, and perhaps have something
reasonable for a future parallel GPU version.
As a side question: has anyone tested Amber with core i7 processors, as
opposed to Xeons? Are there any performance comparisons with regard to
Amber in general, and maybe even GPU version?
Thanks again
Sasha
Levi Pierce wrote:
> When I run my GTX295 which has two GPUs on it only 1 cpu per gpu is pegged
> at 100%
> usage. If I run both GPU's I see two of my 4 cores at 100% usage in top.
>
> ~Levi
>
> On Wed, May 26, 2010 at 3:09 PM, Jason Swails <jason.swails.gmail.com>wrote:
>
>
>> Hello,
>>
>> Currently, multi-CPU/multi-GPU builds are not supported. i.e., if you had
>> 8
>> CPUs with 4 Fermi cards, you could run 4 separate pmemd.cuda simulations
>> that will take up 4 CPU cores and all available GPUs. MPI and CUDA are not
>> currently compatible in the amber build. There's not much need for
>> multiple
>> CPUs, though, since the intensive labor is done on the GPU and the CPU is
>> just there to "supervise" as I see it, though others can give a better
>> explanation. I think the bottleneck currently is communication off-board
>> for the GPU (i.e. each time the GPU has to send information back to the CPU
>> to be printed), discounting the actual calculation for a decently sized
>> system (i.e. parallelizing CPUs doesn't seem worthwhile). Others may chime
>> in and correct minor misconceptions I have about this, but the amber11
>> release does currently only support 1 CPU and 1 GPU, and I think
>> parallelization will go in the direction of making it 1 CPU for multiple
>> GPUs, not the other way around.
>>
>> All the best,
>> Jason
>>
>> On Wed, May 26, 2010 at 5:09 PM, Sasha Buzko <obuzko.ucla.edu> wrote:
>>
>>
>>> Hi all,
>>> has anyone done any comparison testing to determine the optimal number of
>>> CPU cores per executing GPU?
>>> I'm thinking of putting together a GPU system to run Amber. In this case,
>>> would a single quad core Xeon be enough for four (4) Fermi cards (GTX480,
>>> for example)? One core per card, in this case. Or should I really go for
>>>
>> a
>>
>>> 2:1 ratio and a dual quad-core cpu with fewer GPUs?
>>> Are there any other considerations for a multi-GPU hardware
>>>
>> configuration?
>>
>>> Thanks for any advice
>>>
>>> Sasha
>>>
>>>
>>> _______________________________________________
>>> AMBER mailing list
>>> AMBER.ambermd.org
>>> http://lists.ambermd.org/mailman/listinfo/amber
>>>
>>>
>>
>> --
>> Jason M. Swails
>> Quantum Theory Project,
>> University of Florida
>> Ph.D. Graduate Student
>> 352-392-4032
>> _______________________________________________
>> AMBER mailing list
>> AMBER.ambermd.org
>> http://lists.ambermd.org/mailman/listinfo/amber
>>
>>
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Received on Wed May 26 2010 - 16:00:04 PDT
