CW-Ghost: Search-Free Granularity Selection for Helper-Thread Prefetching via Capacity Windows

CW-Ghost addresses the problem of costly granularity selection in helper-thread prefetching by proposing a search-free method. The method uses a single offline profiling run to estimate demand cache line fill volume and combines it with a cache capacity budget to derive a Capacity Window for iteration granularity. Experimental evidence on Intel and AMD platforms shows geometric mean speedups of 1.54x and 1.33x over original programs, and 15.8% and 10.8% improvements over Ghost Threading, achieving over 99% of optimal performance. This matters because it demonstrates that cache capacity constraints can effectively and efficiently guide helper-thread prefetching granularity without exhaustive configuration search.