1. A method for directory-based cache coherence in a multi-core processor system that includes a main memory, a plurality of processor cores and a plurality of caches each associated with a respective one of the plurality of processor cores, the method comprising: providing a directory descriptor cache in the multi-core processor system, the directory descriptor cache being associated with a subset of the plurality of processor cores in the multi-core processor system; storing a directory descriptor in the directory descriptor cache, the directory descriptor being configured to provide an indication of cache sharing status of a respective set of memory locations of the main memory; and updating the directory descriptor stored in the directory descriptor cache in response to one of the plurality of processor cores in the subset of the plurality of processor cores accessing the respective set of memory locations of the main memory.