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Added Bonus Section implementing a proper Parker

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The problems addressed in the earlier version led to an "incorrect"
example which is bad to pass along after reading a whole book. after
getting some feedback in #2 i decided to show how we can create a
proper `Parker`.

The main example (which I assume most interested readers will copy) now
uses a proper parking thechnique so there should be no more dataraces
left.

I also removed the "Reader Excercise" paragraph suggesting that they
explore a way to implement proper parking since we now show that in
our main example.
This commit is contained in:
Carl Fredrik Samson
2020-04-13 14:16:32 +02:00
parent f4b2029788
commit d9eb756ef7
10 changed files with 441 additions and 240 deletions
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9
book/conclusion.html
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@@ -164,15 +164,6 @@ I'll try my best to respond to each one of them.</p>
<p>So our implementation has taken some obvious shortcuts and could use some improvement.
Actually digging into the code and try things yourself is a good way to learn. Here are
some good exercises if you want to explore more:</p>
<h3><a class="header" href="#avoid-threadpark" id="avoid-threadpark">Avoid <code>thread::park</code></a></h3>
<p>The big problem using <code>Thread::park</code> and <code>Thread::unpark</code> is that the user can access these
same methods from their own code. Try to use another method to suspend our thread and wake
it up again on our command. Some hints:</p>
<ul>
<li>Check out <code>CondVars</code>, here are two sources <a href="https://en.wikipedia.org/wiki/Monitor_(synchronization)#Condition_variables">Wikipedia</a> and the
docs for <a href="https://doc.rust-lang.org/stable/std/sync/struct.Condvar.html"><code>CondVar</code></a></li>
<li>Take a look at crates that help you with this exact problem like <a href="https://github.com/crossbeam-rs/crossbeam">Crossbeam </a>(specifically the <a href="https://docs.rs/crossbeam/0.7.3/crossbeam/sync/struct.Parker.html"><code>Parker</code></a>)</li>
</ul>
<h3><a class="header" href="#avoid-wrapping-the-whole-reactor-in-a-mutex-and-pass-it-around" id="avoid-wrapping-the-whole-reactor-in-a-mutex-and-pass-it-around">Avoid wrapping the whole <code>Reactor</code> in a mutex and pass it around</a></h3>
<p>First of all, protecting the whole <code>Reactor</code> and passing it around is overkill. We're only
interested in synchronizing some parts of the information it contains. Try to refactor that