Does this slide give the definition of transactional memory? What is transactional memory? Is it defined anywhere in the lecture notes?
HLAHat
Well, this slide has a bit more data about it. Basically, Transactional Memory is just memory that implements memory transactions. The nice thing about having the memory itself handle the transactional logic is that it takes some burden off the programmer.
admintio42
What exactly does commit mean here? Is it that memory has been changed or that the change is visible?
HLAHat
A committed write is one that is observed by all other processors. So, after a committed write to some value X, any other processor that reads from X will see the newly written value.
kayvonf
Correct, and a transaction's commit simultaneously and atomically commits are memory writes that occurred within the boundaries of the transaction.
lament
@HLAHat In addition to taking the burden off the programmer, if the system is implemented in hardware, it will likely be faster (or can be) than software solutions.
Zarathustra
Transactional memory is two housemates cleaning a house, where one has bleach and the other has ammonia. They start cleaning different parts of the house in parallel, but then arrive at the bathroom. One proposes to use bleach to clean the bathroom. He is about to use it, when the other proposes ammonia. The first housemate decides to hold off on the bleach until the other has used the ammonia and it has dissipated. When the second housemate is done, the first one finishes up cleaning with with his ammonia.
Does this slide give the definition of transactional memory? What is transactional memory? Is it defined anywhere in the lecture notes?
Well, this slide has a bit more data about it. Basically, Transactional Memory is just memory that implements memory transactions. The nice thing about having the memory itself handle the transactional logic is that it takes some burden off the programmer.
What exactly does commit mean here? Is it that memory has been changed or that the change is visible?
A committed write is one that is observed by all other processors. So, after a committed write to some value X, any other processor that reads from X will see the newly written value.
Correct, and a transaction's commit simultaneously and atomically commits are memory writes that occurred within the boundaries of the transaction.
@HLAHat In addition to taking the burden off the programmer, if the system is implemented in hardware, it will likely be faster (or can be) than software solutions.
Transactional memory is two housemates cleaning a house, where one has bleach and the other has ammonia. They start cleaning different parts of the house in parallel, but then arrive at the bathroom. One proposes to use bleach to clean the bathroom. He is about to use it, when the other proposes ammonia. The first housemate decides to hold off on the bleach until the other has used the ammonia and it has dissipated. When the second housemate is done, the first one finishes up cleaning with with his ammonia.