Filtering directory lookups in CMPs

We evaluate our filters in a CMP with 8 in-order processors with 4 threads each and a memory hierarchy with write-through local caches and a shared cache. We show that, for SPLASH2 benchmarks, the proposed filters reduce the number of directory lookups performed by 60% while power consumption is reduced by ∼28%. For Specweb2005, the number of directory lookups performed is reduced by 68% (44%), while directory power consumption is reduced by 19% (9%) using the first (second) filter implementation.