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Questions and Answers
When using transactional memory in a parallel program, which of the ACID properties (associated with database transactions) must be satisfied? Select all correct answers.
When using transactional memory in a parallel program, which of the ACID properties (associated with database transactions) must be satisfied? Select all correct answers.
- Atomicity (correct)
- Consistency
- Isolation (correct)
- Durability
In a parallel program using transactional memory, what happens when two transactions attempt to write to the same memory location?
In a parallel program using transactional memory, what happens when two transactions attempt to write to the same memory location?
- The write that is completed first wins, and the second write is ignored.
- The program crashes.
- Nothing. This can never happen because the transactional memory mechanism prevents it.
- One or both transactions abort, rollback, and restart execution at the beginning of the transaction. (correct)
- One transaction waits until the other commits, and then retries the write.
In a parallel program, a transaction can be used to replace what type(s) of synchronization? Select all correct answers.
In a parallel program, a transaction can be used to replace what type(s) of synchronization? Select all correct answers.
- fetch-and-add instruction (correct)
- mutual exclusion lock (correct)
- barrier
- post/wait synchronization
Suppose we are using transactional memory to parallelize accesses to a linked list. We choose a coarse-grained transactional approach, in which we mark all Insert and Delete operations as atomic. The third operation is Search, which returns true/false based on whether a particular value is found in the list. If we do not mark the Search operation as atomic, what could happen?
Select all correct answers.
Suppose we are using transactional memory to parallelize accesses to a linked list. We choose a coarse-grained transactional approach, in which we mark all Insert and Delete operations as atomic. The third operation is Search, which returns true/false based on whether a particular value is found in the list. If we do not mark the Search operation as atomic, what could happen?
Select all correct answers.
When using hardware transactional memory, which mechanism is used to detect a conflict?
When using hardware transactional memory, which mechanism is used to detect a conflict?
When using hardware transactional memory, the value written to a memory location by an uncommitted transaction is speculative, and it must be temporarily stored before becoming visible to the rest of the processors.
Where are possible locations in which the speculative state can be stored? Select all correct answers.
When using hardware transactional memory, the value written to a memory location by an uncommitted transaction is speculative, and it must be temporarily stored before becoming visible to the rest of the processors.
Where are possible locations in which the speculative state can be stored? Select all correct answers.
In transactional memory, which of the following conditions represents a conflict? Select all correct answers.
In transactional memory, which of the following conditions represents a conflict? Select all correct answers.
Explain Speculative Lock Elision
Explain Speculative Lock Elision
Explain Transactional Lock Removal
Explain Transactional Lock Removal
Flashcards
Capital of France (example flashcard)
Capital of France (example flashcard)
Paris
