I have a cilk program that is using the libpuzzle library. My task is to parallelize the sorting of images based on their resemblance and I am using a parallel cilk for loop to compare all the images with a reference image. What I noticed was that on the first run of the program the execution was slow, but after the second run it speeds up and I could see all the logical cores working at 100%... I repeated this every time i built the project and always ra two runs and this performance could be seen. Any ideas what might cause a parallel program to run slightly bad on the first run and good on the second run. I changed the image distributions as well and this pattern seems to hold. If anyone has had similar experiences could you please share what you did to fix the problem?
Thank you