Difference between real time, CPU time and elapsed time?

- May 4, 2021 at 2:20 pm
  
  vineethap
  Subscriber
  
  Hi,
  I am working on 3D electrical machine modelling in Ansys Maxwell. I would like to know the difference between real time, CPU time and elapsed time.
- May 6, 2021 at 11:38 am
  
  VivekKamble
  Ansys Employee
  
  CPU time can be either accumulated by all of the involved processors (or cores), or it can be the CPU time for any of the involved processors (or cores). CPU time may exclude time spent waiting for data to be passed through the interconnector the time spent waiting for I/O requests to be completed.
  
  Elapsed times provide the best measure of what the user actually experiences while waiting for the program to complete the analysis.
  
  When using Distributed ANSYS, the main values to review are:
  The "Elapsed time spent computing solution" measures the time spent doing parallel work inside theSOLVEcommand.
  The "Elapsed Time" reported at the end of the output file.
  The "Elapsed time spent computing solution" helps measure the parallel efficiency for the computations that are actually parallelized, while the "Elapsed Time" helps measure the parallel efficiency for the entire analysis of the model. Studying the changes in these values as the number of cores is increased/decreased will give a good indication of the parallel efficiency of Distributed ANSYS for your analysis.
  When using a GPU to accelerate the solution, the same main values listed above should be reviewed. Since the GPU is currently only used to accelerate computations performed during the solution, the elapsed time computing the solution is the only time expected to decrease. Of course, the overall time for the simulation should also decrease when using a GPU.
  
  Regards Vivek