I have an array of 1000-2000 elements which are pointers to objects. I want to keep my array sorted and obviously I want to do this as quick as possible. They are sorted by a member and not allocated contiguously so assume a cache miss whenever I access the sort-by member.
Currently I’m sorting on-demand rather than on-add, but because of the cache misses and [presumably] non-inlining of the member access the inner loop of my quick sort is slow.
I’m doing tests and trying things now, (and see what the actual bottleneck is) but can anyone recommend a good alternative to speeding this up?
Should I do an insert-sort instead of quicksorting on-demand, or should I try and change my model to make the elements contigious and reduce cache misses?
OR, is there a sort algorithm I’ve not come accross which is good for data that is going to cache miss?
Edit: Maybe I worded this wrong :), I don’t actually need my array sorted all the time (I’m not iterating through them sequentially for anything) I just need it sorted when I’m doing a binary chop to find a matching object, and doing that quicksort at that time (when I want to search) is currently my bottleneck, because of the cache misses and jumps (I’m using a < operator on my object, but I’m hoping that inlines in release)
Simple approach: insertion sort on every insert. Since your elements are not aligned in memory I’m guessing linked list. If so, then you could transform it into a linked list with jumps to the 10th element, the 100th and so on. This is kind of similar to the next suggestion.
Or you reorganize your container structure into a binary tree (or what every tree you like, B, B*, red-black, …) and insert elements like you would insert them into a search tree.