Why cycles engine renders in how many samples it wants, not how many i give it? Today i tried making a scene, normal procedure for starting work in blender, switch to cycles, delete cube, make my scene and finally give it full render to see how it came out. Surprise, at first it didnÂt want to render in more than 40 samples no matter what i put in "sampling -> render"
 All good, i said, restart, maybe after that will work. Not only i lost my work (but that because i forgot to save) But when i opened it again, i did nothing except switch to cycles and increase sample count. I put it to 100 and give it render, only to see that it rendered 135 samples. What is happening and how i fix?
Here is image of problem circled with white:
The number you see on the top is the number of tiles that have been rendered, not the number of samples. In your case the image has been split into 135 path tracing tiles. 



You have set a render tile size in pixels in the performance tab. The image gets divided in as many tiles of those dimensions as it needs to rrender the image.