1. A method comprising: detecting a cache miss for a requested cache line in a cache sectored into superlines, each superline including multiple cache lines; generating a request vector in response to detecting the cache miss, the request vector including a field for each cache line of the superline, the generating including placing a demand request in the field for the cache line that caused the cache miss; modifying the request vector with prefetch hint information for one or more of the other cache lines allocated in the superline; and sending the request vector to a higher level memory to cause the higher level memory to satisfy the demand request, wherein the higher level memory selectively either performs prefetches for other cache lines of the superline based on the prefetch hint information or drops the prefetch hint information.