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amaliujia

Is is possible that CPU uses mechanism like lease to manage cache coherence and consistency? Lease is widely used in distributed systems.

ankit1990

@amaliujia Leases in distributed systems are used as a fault tolerant mechanism. I am not sure why leases are necessary since the probability of a failure for different entities involved is almost negligible (unlike distributed systems).

amaliujia

@ankit1990 For instance, assume there are 3 processors. For now, 2 of them keep a cache line with a read lease. If the third line want a write lease, it has to wait until two read leases expired. This can still hold order of operations with some cost.

VP7

Wont it make the design even more complex? Wont it introduce the overhead of additional book-keeping?

zhiyuany

@amaliujia, using lease need atomic guarantee on lease operation, which means you duplicate the problem you want to solve by using lease.