Methods and apparatus of cache access to a data array with locality-dependent latency characteristics

An apparatus comprising:

• a data array having locality-dependent latency characteristics such that an access to an open unit of the data array has a lower latency than an access to a closed unit of the data array;
• set associative cache indexing circuitry to determine, in response to a request for data associated with a target address, a cache set index corresponding to the target address;
• mapping circuitry to identify, in response to the cache set index, a set of data array locations of the data array corresponding to the cache set index, according to a mapping in which a given unit of the data array comprises data array locations corresponding to a plurality of consecutive set indices, and at least two memory locations of the set of data array locations corresponding to the same cache set index are in different units of the data array;
• and
• cache access circuitry to access said data associated with the target address from one of the set of data array locations identified by the mapping circuitry.