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How to use the repository alongside the book – Creating Our Own Fibers
The recommended way to read this chapter is to have the repository open alongside the book. In the repository, you’ll find three different folders that correspond to the examples we go through in this chapter: In addition, you will get two more examples that I refer to in the book but that should be explored…
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Technical requirements – Creating Our Own Fibers
In this chapter, we take a deep dive into a very popular way of handling concurrency. There is no better way of getting a fundamental understanding of the subject than doing it yourself. Fortunately, even though the topic is a little complex, we only need around 200 lines of code to get a fully working…
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Summary – Create Your Own Event Queue
The concept of epoll, kqueue, and IOCP is pretty simple at a high level, but the devil is in the details. It’s just not that easy to understand and get it working correctly. Even programmers who work on these things will often specialize in one platform (epoll/kqueue or Windows). It’s rare that one person will…
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BE CAREFUL WITH USING TCPSTREAM::READ_TO_END – Create Your Own Event Queue
You should be careful with using TcpStream::read_to_end or any other function that fully drains the buffer for you when using non-blocking buffers. If you get an error of the io::WouldBlock type, it will report that as an error even though you had several successful reads before you got that error. You have no way of…
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The main program – Create Your Own Event Queue
Let’s see how it all works in practice. Make sure that delayserver is up and running, because we’ll need it for these examples to work. The goal is to send a set of requests to delayserver with varying delays and then use epoll to wait for the responses. Therefore, we’ll only use epoll to track…
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Level-triggered versus edge-triggered events – Create Your Own Event Queue
In a perfect world, we wouldn’t need to discuss this, but when working with epoll, it’s almost impossible to avoid having to know about the difference. It’s not obvious by reading the documentation, especially not if you haven’t had previous experience with these terms before. The interesting part of this is that it allows us…
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The ffi module – Create Your Own Event Queue-2
The last part of the code in this file is the Event struct: ch04/a-epoll/src/ffi.rs#[derive(Debug)]#[repr(C, packed)]pub struct Event { pub(crate) events: u32, // Token to identify event pub(crate) epoll_data: usize,}impl Event { pub fn token(&self) -> usize { self.epoll_data }} This structure is used to communicate to the operating system in epoll_ctl, and the operating system uses the same structure to communicate…
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Is all I/O blocking? – Create Your Own Event Queue
Finally, a question that’s easy to answer. The answer is a big, resounding… maybe. The thing is that not all I/O operations will block in the sense that the operating system will park the calling thread and it will be more efficient to switch to another task. The reason for this is that the operating…
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IMPORTANT NOTE – Create Your Own Event Queue
By moving the concern of registering interests to a separate struct like this, users can call Registry::try_clone to get an owned Registry instance. This instance can be passed to, or shared through Arc<Registry> with, other threads, allowing multiple threads to register interest to the same Poll instance even when Poll is blocking another thread while…
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THE DELAY SERVER – Create Your Own Event Queue
This example relies on calls made to a server that delays the response for a configurable duration. In the repository, there is a project named delayserver in the root folder. You can set up the server by simply entering the folder in a separate console window and writing cargo run. Just leave the server running…
