Sanat Vij

At a time where the clock speeds of processors have been stable over the past couple of years, and Moore's Law is instead being applied by increasing the number of processor cores, it is getting more important for applications to use concurrent processing to reduce run/response times, as the time slicing routine via increased clock speed will no longer be available to bail out slow running programs. Carl Hewitt proposed the Actor Model in 1973 as a way to implement unbounded nondeterminism in concurrent processing. In many ways this model was influenced by the packet switching mechanism, for example, no synchronous handshake between sender and receiver, inherently concurrent message passing, messages may not arrive in the order they were sent, addresses are stored in messages, etc. The main difference between this model and most other parallel processing systems i... (more)

Dealing with Application Deadlocks

A deadlock is a situation where two or more threads are blocked while waiting to obtain locks that some of the other threads in the deadlock are holding. Deadlocks can occur when multiple threads need the same locks, at the same time, but obtain them in different order. For instance, if thread 1 locks A, and tries to lock B, and thread 2 has already locked B, and tries to lock A, a deadlock arises. Thread 1 can never get B, and thread 2 can never get A. In addition, neither of them will ever know. They will remain blocked on each of their objects, A and B, forever. Deadlock Dete... (more)