Octave processor loading on 6-DoF simulation

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Octave processor loading on 6-DoF simulation

Francois du Plessis
Hallo
I am using Octave to run a 6-DoF trajectory simulation. Until quite recently I used Matlab to run this simulation, but had to revert to Octave due to licensing issues.  The simulation has numerous look-up tables (for the aerodynamics) with the main execution performed using the customary recursive loop for the closed-loop control system implementation.  I noticed the following:
  • Matlab performed the simulation in about 2 minutes
  • Octave takes 22 minutes to perform the same simulation.
  • Matlab was (I think) flooring the processor
  • Octave is only using 8% of the processor with the processor being about 90% idle.  It is not nearly using all the available RAM.
What would the reason be that Octave is not using all the system resources?  Is is because it is only making use of a single processor?  Windows task manager indicates that all 12 cores are sporadically activated, but I would have thought that this type of task would push the processor(s) into the red - at least one of them...

Does anyone have an idea why this would be or what can be done to improve the utilization?  I have already adjusted the task priority, but this does not do anything.

Thanks
Francois

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Re: Octave processor loading on 6-DoF simulation

Ozzy Lash


On Wed, Jan 10, 2018 at 6:35 AM, Francois du Plessis <[hidden email]> wrote:
Hallo
I am using Octave to run a 6-DoF trajectory simulation. Until quite recently I used Matlab to run this simulation, but had to revert to Octave due to licensing issues.  The simulation has numerous look-up tables (for the aerodynamics) with the main execution performed using the customary recursive loop for the closed-loop control system implementation.  I noticed the following:
  • Matlab performed the simulation in about 2 minutes
  • Octave takes 22 minutes to perform the same simulation.
  • Matlab was (I think) flooring the processor
  • Octave is only using 8% of the processor with the processor being about 90% idle.  It is not nearly using all the available RAM.
What would the reason be that Octave is not using all the system resources?  Is is because it is only making use of a single processor?  Windows task manager indicates that all 12 cores are sporadically activated, but I would have thought that this type of task would push the processor(s) into the red - at least one of them...

Does anyone have an idea why this would be or what can be done to improve the utilization?  I have already adjusted the task priority, but this does not do anything.

Thanks
Francois


It seems suspicious that you way that Octave is using 8% of the CPU and you have 12 cores.  Are you sure that Octave isn't maxing out one core  (1/12 is 8.3%).  I think that Octave can use a threaded version of atlas but you may need to adjust the libatlas link to be libtatlas instead of libsatlas, or maybe this happens at compile time.  However, I am not sure if that would help your workload.

Just a thought.

Bill

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