Question

Please discuss principle of locality and how it applies to exploiting memory hierarchy to achieve higher performance.

Answer 1

Answer)

In the principle of locality scenario, this is a phenomenon where the same values are frequently accessed and this depends on the memory access pattern. The 2 types of referential locality are:

temporal locality

and spatial locality

Temporal locality is the reuse of data and resources within a defined specific duration. Temporal locality believes that when a memory location is accessed or referenced, then the same location will be referred or accessed again in the future within a certain time period.

The spatial locality is about when the storage location is referenced at a time, then it should be known and can be guessed that that memory location or such nearby locations can and will be accessed in the future. Thus, it will be an advantage to store the size, area, addresses around the references such that faster access can be provided for future references to that memory object.

Now, principle of locality is required for the predictable behavior in computer systems where we get to predict the usage of the resources. Also, for efficient use and utilization of the memory the principle of locality is used in cache and virtual memories. As cache and virtual memories function on the most recent accessed items which are stored in the memory so that the processor can access and execute the instruction using the resources in the cache rather than going all the way from primary to secondary memory, thus principle of locality allows for faster execution and also efficient use of the memory - cache, virtual, main memory and secondary memories.

If there was no locality of reference the performance would have degraded and thus there would have been no reuse and different categorization of the memories would have been useless and futile.