The speedup achieved in the DEM simulations of 2 mm particles. There was a linear increase up to 16 cores, then as the parallel efficiency decreased, plateauing of the speedup is observed.
speed-up is a way to measure parallel efficiency. Thus, saying, "... (consequence of) parallel efficiency decreased, plateauing of the speedup is observed." is misleading or tautological.
The speedup achieved in the DEM simulations of 2 mm particles. There was a linear increase up to 16 cores, then as the parallel efficiency decreased, plateauing of the speedup is observed.