For inclusion to hold between two cache levels L1 and L2 in a multi-level cache hierarchy, which of the following are necessary?
- L1 must be a write-through cache.
- L2 must be a write-through cache.
- The associativity of L2 must be greater than that of L1.
- The L2 cache must be at least as large as the L1 cache.
This was a multiple-choice question with the following possible answers:
- (A) 4 only
- (B) 1 and 4 only
- (C) 1, 2 and 4 only
- (D) 1, 2, 3 and 4
I think L2 cache must be at least as large as the L1 cache but I am confused what the need for writeback is for this cache.