1. A method, comprising: filtering a probe of at least one of a plurality of first caches based on a plurality of first bits associated with a line indicated by the probe, wherein each of the plurality of first bits is associated with a different subset of the plurality of first caches, and wherein each first bit indicates whether the line is resident in a corresponding subset of the plurality of first caches, and wherein a second bit indicates whether the line is resident in more than one of the plurality of first caches in at least one of the subsets of the plurality of first caches.