While looking at cycles source code trying to fix a UV issue on hair issue, I noticed that we were not taking into account the display_percentage during IPR. Also, we can shorten the loop range when there are child particles.
While looking at cycles source code trying
to fix a UV issue on hair issue, I noticed that
we were not taking into account the display_percentage during IPR.
Also, we can shorten the loop range when
there are child particles.

prman-pixar/RenderManForBlender,prman-pixar/RenderManForBlender