Self-healing coarse-grained snoop filter

A coherent multiprocessor system, comprising:

• multiple local processing units that each have a Level-1 (L1) cache;
• a Level-2 (L2) cache shared among the multiple local processing units, wherein the L2 cache includes a snoop filter configured to track entries in the L1 cache associated with each local processing unit;
• and
• a processor configured to:
• receive a request to update a target memory location at the L2 cache;
• perform a lookup in the snoop filter based on the target memory location;
• select a victim entry to evict from the snoop filter in response to the lookup missing the snoop filter and the snoop filter lacking available space to store a new entry that corresponds to the target memory location;
• send a request to invalidate every cache line that maps to the selected victim entry to at least one of the multiple processing units that has one or more cache lines that map to the selected victim entry in the L1 cache associated therewith;
• and
• replace the selected victim entry in the snoop filter with the new entry that corresponds to the target memory location.

An apparatus, comprising:

• means for receiving a request to update a target memory location at a non-inclusive Level-2 (L2) cache shared among multiple local processing units that each have a Level-1 (L1) cache;
• means for performing a lookup based on the target memory location in a snoop filter that tracks entries in the L1 cache associated with each local processing unit;
• means for selecting a victim entry to evict from the snoop filter in response to the lookup missing the snoop filter and the snoop filter lacking available space to store a new entry that corresponds to the target memory location;
• means for sending a request to invalidate every cache line that maps to the selected victim entry to at least one of the multiple processing units that has one or more cache lines that map to the selected victim entry in the L1 cache associated therewith;
• and
• means for replacing the selected victim entry in the snoop filter with the new entry that corresponds to the target memory location.

A computer-readable medium storing computer-executable instructions, the stored computer-executable instructions configured to cause one or more processors to:

• receive a request to update a target memory location at a non-inclusive Level-2 (L2) cache shared among multiple local processing units that each have a Level-1 (L1) cache;
• perform a lookup based on the target memory location in a snoop filter that tracks entries in the L1 cache associated with each local processing unit;
• select a victim entry to evict from the snoop filter in response to the lookup missing the snoop filter and the snoop filter lacking available space to store a new entry that corresponds to the target memory location;
• send a request to invalidate every cache line that maps to the selected victim entry to at least one of the multiple processing units that has one or more cache lines that map to the selected victim entry in the L1 cache associated therewith;
• and
• replace the selected victim entry in the snoop filter with the new entry that corresponds to the target memory location.