A technique for prefetching data for a cache is provided. The technique includes detecting access to a data block. In response to the detection, a prefetch block generates proposed blocks for prefetch. The prefetch block also examines prefetch tracking data to determine whether a prefetch group including the proposed blocks is marked as already having been prefetched. If the group has been marked as already having been prefetched, then prefetch block does not prefetch that data, thereby avoiding traffic between the prefetch block and the cache memory. Using this technique, unnecessary requests to prefetch data into the cache memory are avoided.