Cache line contention

A method of operating a cache interconnect comprising:

• storing, in snoop circuitry of the cache interconnect, a table containing an entry, for each of a plurality of cache lines, comprising a cache line identifier, an indication of a most recent processing element of a plurality of processing elements associated with the cache interconnect to access the cache line, and an indication of a data item in the cache line which was identified by the most recent processing element to be accessed;
• receiving, by the snoop circuitry, a request from a requesting processing element of the plurality of processing elements, the request identifying a requested data item;
• determining, by the snoop circuitry, a requested cache line identifier corresponding to the requested data item;
• providing, by the snoop circuitry and responsive to determining that the requested cache line identifier is stored in an identified entry in the table, and based on the requested data item and the indication of the data item in the table, an identity indication as to whether the requested data item is the same as the data item in the identified entry;
• and
• in response to the identity indication showing that the requested data item is not the same as the data item in the entry for the requested cache line, incrementing a value held by a false sharing counter.

An apparatus comprising:

• means for storing a table containing an entry, for each of a plurality of cache lines, comprising a cache line identifier, an indication of a most recent processing element of a plurality of processing elements associated with a cache interconnect to access the cache line, and an indication of a data item in the cache line which was identified by the most recent processing element to be accessed;
• means for receiving a request from a requesting processing element of the plurality of processing elements, the request identifying a requested data item to be accessed;
• means for determining a requested cache line identifier corresponding to the requested data item;
• means for providing, responsive to determining that the requested cache line identifier is stored in an identified entry in the table, and based on the requested data item and the indication of the data item in the table, an identity indication as to whether the requested data item is the same as the data item in the identified entry;
• and
• responsive to the identity indication showing that the requested data item is not the same as the data item in the entry for the requested cache line, means for incrementing a value held by a false sharing counter.