[20] <2.1, 2.2, 2.3> A cache acts as a filter. For example, for every 1000 instructions of a program, an average of 20 memory accesses may exhibit low enough locality that they cannot be serviced by a 2 MB cache. The 2 MB cache is said to have an MPKI (misses per thousand instructions) of 20, and this will be largely true regardless of the smaller caches that precede the2 MB cache. Assume thefollowing cache/latency/MPKI values: 32 KB/1/100, 128 KB/2/80, 512 KB/4/50, 2 MB/8/40, 8 MB/16/10. Assume that accessing the off-chip memory system requires 200 cycles on average. For the following cache configurations, calculate the average time spent accessing the cache hierarchy. What do you observe about the downsides of a cache hierarchy that is too shallow or too deep? a. 32 KB L1; 8 MB L2; off-chip memory b. 32 KB L1; 512 KB L2; 8 MB L3; off-chip memory c. 32 KB L1; 128 KB L2; 2 MB L3; 8 MB L4; off-chip memory