Performance impact due to time required for shuffling in Quicksort As a programmer with non CS background, I am learning algorithms.

When explaining the performance of quicksort in an Algorithm book and also elsewhere on the web, I do not see any reference to the time/space needed for shuffling. I do understand that shuffling is important to have the $O(n\log n)$ performance, but shuffling itself would have a complexity of $O(n)$. Why does this become irrelevant in the total performance?
The short answer is that the $O(n\log n)$ component dominates the $O(n)$ component, hence the $O(n)$ part can be ignored in the statement of complexity.