Messages in this thread | | | From | "John Yau" <> | Subject | Re: Priority Inversion in Scheduling | Date | Wed, 10 Sep 2003 01:41:33 -0400 |
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> > Well I haven't read the paper, but I'm guessing this is semaphore > priority inheritance. >
Yip...it outlines the basic idea of the priority inheritance where semphores are the locking mechanism. However, though it buys you better prioritized scheduling in certain situation, things can get rather hairy when you have lots of semaphores nested inside each other. If you have a cyclic dependency somewhere in those nested semaphores, you're headed for deadlock or worse livelock. The Mars Rover had a classic case of priority inversion in it's software that was later solved through this approach via an update after it landed on Mars a while back.
> > I _think_ communication with X will mostly be done with waitqueues. > Someone has a priority inheritance futex patch around. I'm not sure > that it is such an open and shut case as you think though. Even if you > could use futexes in communication with X. >
It's not an open and shut case...actually it'd be quite an undertaking I suspect. Because a poorly designed and/or poorly implemented scheme can easily lead to deadlocks and what not, any implementation would need massive peer review. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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