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)
“Then, anger
was a crease in the brow
and silence
a catastrophe.
Then, making up
was a mutual smile
and a glance
a gift.
Now, just look at this mess
that you’ve made of that love.
You grovel at my feet
and I berate you
and can’t let my anger go.”
—Amaru (c. seventh century A.D.)
“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)