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None from 8 cores to 80 cores with no speed increase 

Forum: Multithreading
Date: 11 Aug, 2015
From: matthew <matthew>

Hello GEANT users,

I am running a simulation to model fluorescence in the atmosphere and recently moved my code up to the super computer in an attempt to increase speed of execution. Strangely, I don't see a dramatic increase in execution speed from 8 to 80 cores. Shouldn't I see a 10 fold increase in speed?

I am using primitive scorers to record energy deposition. Is that the reason? Does threading only increase speed of user hooks?

I've attached the output from both runs to this post. The number of cores used can be found in the first several lines, and the speed of execution can be found near the bottom of the output.

I would appreciate any guidance on why I don't see a dramatic increase in execution time.

thanks,
matthew

   Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2015/08/11/17.24-9777-GEANT_Output_8cores.txt
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2015/08/11/17.24-79392-GEANT_Output_80cores.txt

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1 None: Re: from 8 cores to 80 cores with no speed increase   (lcl - 12 Aug, 2015)
2 Warning: Re: from 8 cores to 80 cores with no speed increase   (Andrea Dotti - 12 Aug, 2015)
1 Question: Re: from 8 cores to 80 cores with no speed increase   (matthew - 13 Aug, 2015)
(_ Warning: Re: from 8 cores to 80 cores with no speed increase   (Andrea Dotti - 13 Aug, 2015)
(_ None: Re: from 8 cores to 80 cores with no speed increase   (matthew - 13 Aug, 2015)
(_ Idea: Re: from 8 cores to 80 cores with no speed increase   (Andrea Dotti - 13 Aug, 2015)
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