Advanced Mutual Exclusion
Synchronization primitives can be built like the examples below by using the solutions explained above:
- Locks
- Reentrant mutexes
- Semaphores
- Monitors
- Message passing
- Tuple space
Many forms of mutual exclusion have side-effects. For example, classic semaphores permit deadlocks, in which one process gets a semaphore, another process gets a second semaphore, and then both wait forever for the other semaphore to be released. Other common side-effects include starvation, in which a process never gets sufficient resources to run to completion, priority inversion in which a higher priority thread waits for a lower-priority thread, and "high latency" in which response to interrupts is not prompt.
Much research is aimed at eliminating the above effects, such as by guaranteeing non-blocking progress. No perfect scheme is known.
Read more about this topic: Mutual Exclusion
Famous quotes containing the words advanced, mutual and/or exclusion:
“I don’t say ‘tis impossible for an impudent man not to rise in the world, but a moderate merit with a large share of impudence is more probable to be advanced than the greatest qualifications without it.”
—Mary Wortley, Lady Montagu (1689–1762)
“Rules and particular inferences alike are justified by being brought into agreement with each other. A rule is amended if it yields an inference we are unwilling to accept; an inference is rejected if it violates a rule we are unwilling to amend. The process of justification is the delicate one of making mutual adjustments between rules and accepted inferences; and in the agreement achieved lies the only justification needed for either.”
—Nelson Goodman (b. 1906)
“All men, in the abstract, are just and good; what hinders them, in the particular, is, the momentary predominance of the finite and individual over the general truth. The condition of our incarnation in a private self, seems to be, a perpetual tendency to prefer the private law, to obey the private impulse, to the exclusion of the law of the universal being.”
—Ralph Waldo Emerson (1803–1882)