Abstract: Techniques are disclosed relating to cache coherency and snoop filtering. In some embodiments, an apparatus includes multiple processor cores and corresponding filter circuitry that is configured to filter snoops to the processor cores. The filter circuitry may implement a Bloom filter. The filter circuitry may include a first set of counters. The filter circuitry may determine a group of counters in the first set based on applying multiple hash functions to an incoming address. For allocations, the filter circuitry may increment the counters in the corresponding group of counters; for evictions, the filter circuitry may decrement the counters in the corresponding group of counters; and for snoops, the filter circuitry may determine whether to filter the snoop based on whether any of the counters in the corresponding group are at a start value.