vault backup: 2025-04-05 00:05:56
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@ -140,7 +140,7 @@ Easy to generalize to k-MUTEX.
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Peterson's algorithm cost $O(n^2)$
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A first way to reduce this cost is by using a tournament of MUTEX between pairs of processes:
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Of course this is a binary tree, and the height of a binary tree is logaritmic to the number of leaves. A process then wins after $\lceil \log_{2}n \rceil$ competitions $\to O(\log n)$ cost.
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@ -180,7 +180,7 @@ producer A:
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- so producer A will write at `BUF[0]`
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- but wait! Consumer B is still reading there
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- **Producer A doesn't give a fuck.**
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![]()
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*don't be like Producer A, be more like Bob, who always scans EMPTY before!*
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So the issue here is that producers just assume that IN is the first available slot. But it its not necessarily the case.
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@ -3,7 +3,7 @@ The first real practical example of a concurrent system.
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- one chopstick between each pair of philosophers
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- a philosophers must pick up its two nearest chopsticks in order to eat
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- a philosopher must pick up first one chopstick, then the second one, not both at once
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![]()
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**PROBLEM:** *Devise a deadlock-free algorithm for allocating these limited resources (chopsticks) among several processes (philosophers).*
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