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Question What's the best choice for number of processes and threads? 

Forum: Multithreading
Date: 13 Jan, 2017
From: Huan Yao <Huan Yao>

My system Info:
Ubuntu 16.04 64 bit(virtual box on windows 10)
g++ 5.4
geant4 10.3
# of Core: 2

Test my simulation with different mode with ntuple merging option on
Trial-------NP-------Threads--Result (T-good F-Fail)
1(seq mode)-0--------1--------T
2(MT mode)--0--------1--------T
3-----------0--------2--------T
4-----------0--------16-------T
5(MT+MPI)---1--------1--------T
6-----------1--------2--------T
7-----------1--------16-------T
8-----------2--------2--------T
9-----------2--------16-------T
10----------16-------1--------T
11----------16-------16-------F

Only last one failed. The merged root file has weird result, the counts are wrong, the magic number 92 will always pop up ( as you can see in the attachment )

So I try it on the server with 16 cores with 16 NP, the results are good.
To me, the NP*Threads do not excess some limits, the result will be fine.
But how to find this limit?
So my question is as title.

Thanks.

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1 Feedback: Re: What's the best choice for number of processes and threads?   (Andrea Dotti - 13 Jan, 2017)
(_ None: Re: What's the best choice for number of processes and threads?   (Tom Roberts - 13 Jan, 2017)
(_ More: Re: What's the best choice for number of processes and threads?   (Andrea Dotti - 13 Jan, 2017)
(_ None: Re: What's the best choice for number of processes and threads?   (Huan Yao - 13 Jan, 2017)
(_ More: Re: What's the best choice for number of processes and threads?   (Andrea Dotti - 14 Jan, 2017)
(_ None: Re: What's the best choice for number of processes and threads?   (Huan Yao - 17 Jan, 2017)
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