Virtual Labs

What is the primary purpose of cache coherence protocols in multiprocessor systems?

a: To increase the speed of individual processors Explanation

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b: To ensure data consistency across multiple processor caches Explanation

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c: To reduce the size of cache memory required Explanation

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d: To eliminate the need for main memory Explanation

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How many states does the MOESI cache coherence protocol define?

a: Three states Explanation

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b: Four states Explanation

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c: Five states Explanation

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d: Six states Explanation

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In a cache coherence protocol, what does a 'cache miss' typically result in?

a: The processor stops execution Explanation

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b: The data is fetched from main memory or another cache Explanation

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c: The cache line is immediately invalidated Explanation

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d: The processor switches to a different task Explanation

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What is the key advantage of the Exclusive state in cache coherence protocols?

a: It allows multiple processors to write simultaneously Explanation

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b: It prevents any read operations on the data Explanation

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c: It allows transition to Modified state without bus communication Explanation

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d: It automatically invalidates all other cache copies Explanation

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In the MOESI protocol, which state indicates that the cache line is modified and may be shared with other caches?

a: Modified (M) Explanation

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b: Owned (O) Explanation

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c: Exclusive (E) Explanation

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d: Shared (S) Explanation

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What bus operation is typically generated when a processor wants to write to a cache line in Shared state?

a: BusRd Explanation

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b: BusRdX Explanation

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c: BusUpgr Explanation

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d: BusFlush Explanation

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Which of the following best describes the snooping mechanism in cache coherence?

a: Processors actively request cache states from other processors Explanation

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b: All caches monitor bus transactions and update their states accordingly Explanation

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c: A central controller manages all cache states Explanation

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d: Processors randomly check other caches for data consistency Explanation

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In a MOESI system, if Processor A has a cache line in Modified state and Processor B performs a read to the same address, what happens to Processor A's cache line?

a: It transitions to Invalid state Explanation

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b: It remains in Modified state Explanation

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c: It transitions to Owned state Explanation

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d: It transitions to Shared state Explanation

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What is the primary benefit of the Owned state in MOESI compared to simpler protocols like MESI?

a: It eliminates all cache misses Explanation

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b: It allows dirty data sharing without writing back to memory first Explanation

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c: It prevents any coherence traffic on the bus Explanation

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d: It automatically resolves all cache conflicts Explanation

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MOESI Cache Coherence Protocol