Hardware Transactional Memory

Atomicity (correct)

Consistency

Isolation (correct)

Durability

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.

fetch-and-add instruction (correct)

mutual exclusion lock (correct)

barrier

post/wait synchronization

<p>We may return true for a value that has been deleted from the list by another thread during the search.</p> Signup and view all the answers

<p>The cache coherence protocol.</p> Signup and view all the answers

<p>last-level cache</p> Signup and view all the answers

<p>One transaction reads a memory location that is written by a concurrent transaction.</p> Signup and view all the answers

<p>Speculative Lock Elision: Concurrent accesses to a shared data structure might not conflict, and lock/unlock is not, in fact needed. Example: we do some sort of read, then check a variable, where the write is conditional. In this instance, it may not be necessary to lock the entire data structure: Stores to acquire a lock, and release a lock, as a pair have no effect. This is known as a silent store pair. The resulting value of the store is the same as if the stores weren’t even there. This way, we can not acquire the lock, and just do the critical section, and see if it worked.</p> Signup and view all the answers

<p>Like SLE, but does conflict removal by calculating a timestamp and letting the lower timestamp have priority in case of conflict.</p> Signup and view all the answers