[Starpu-devel] StarPU questions

[David Pereira <dspereira004@gmail.com>]

Hi,

Thank you for answering all my previous questions.

I have two more questions where I need your opinion.

I have executed my StarPU version on two GPUs (without CPUs) and on two GPUs + a dual socket CPU (2 NUMA nodes of 6 cores each), and the former is faster for every scheduler that I have used (peager, pheft, ws, dm and dmda). Is this supposed to be normal? I mean, the difference is quite expressive even though I don't have a high level of paralellism, I thought that StarPU would try to minimize the global execution time (and I suppose that it would be by executing most of the tasks on both GPUs). However, StarPU schedules a significant number of tasks on the CPU and this degrades overall performance. I think that this may be normal for the "peager" and "ws" schedulers but not for the other ones.

Also, I'm thinking of trying to use the Xeon Phi. The trunk documentation explains just a little bit how I can work with it. My question is: Does StarPU sees the MIC as a single worker or each of its cores as a single worker?.Or is it just like a normal CPU where I can create combined workers?

Thanks again!

Best Regards,

--

David Pereira