Libevent is pretty cool, but it is not “fast” for all applications. For example, it retrieves the system clock frequently, which can be a performance. libtorque: Portable Multithreaded Continuations decade’s architectures and operating systems, as libevent , libev, Java NIO and others achieved ubiquity much room for improving non-blocking I/O solu- Network programming abounds with task idioms. .. this approach could be the fastest path to true zero- . I want to know how to use libevent l.4,especially the use of http. can anybody give me a Fast portable non-blocking network programming with Libevent.
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Instead of regular events, which give callbacks when the underlying transport is ready to be read or written, a buffer event invokes its user-supplied callbacks when it has read or written enough data.
When we want to libevennt data, for example, the usual pattern looks like: But it’s a tradeoff: Also, I’m not convinced that the “nasty state bugs” from reorganizing around an event loop are necessarily worse than the ones that come from using threads with shared state. On the other end, say you run a thread per socket – that’s not effective as the memory usage for reserving thread stack space will limit your maximum connection count.
Event-based code obscures control flow, as you note; threaded code is subject to very subtle and hard-to-reproduce bugs. The short answer may very well be no, since it somewhat depends on the programming language one chooses to use.
For more information on what the error was, call EventUtil:: Remember how much we wrote, and if we still have more data to write, wait for the connection to become writable again. That means you’ll often be stuck with limited capabilties, unless you write your own libraries or hack up existing ones. Once you set up a non-blocking event loop, it’s much simpler when you can go async all the way down. Numeric file descriptor associated with the buffer event. A “buffer event” consists of an underlying transport like a socketa read buffer, and a write buffer.
Edit Report a Bug. What exactly is it that made this thing the snake oil of the week?
It was used heavily in the 90’s when threaded multiplexing was still new and threads were expensiveand it works well enough. It’s too bad that no standard method for a asynchronous events has been developed for Unix in general.
Equals to NULLif there is no file descriptor socket associated with the buffer event. Usually an application wants to perform some amount of data buffering in addition to just responding to events.
RoboTeddy on Jan 11, If I had to speculate: But pgogramming apps don’t fall into those categories, and I’m not getting any of that vibe from this. Iwth of it is still relevant, though it was written before scary parallel SMP became common 8-way is routine for a server these days. But it’s difficult and error-prone. An event occured during a read operation on the bufferevent.
Fast portable non-blocking network programming with Libevent | Hacker News
It’s one of those things that I’ve read about different methods here and there, but I’ve never come across one good source that compared and contrasted the various techniques. It seems like a good fit for both the indexing hubs and the storage nodes, and it pairs well with Lua’s coroutines.
Properties fd Numeric file descriptor associated with the buffer event. Normally represents a bound socket.
PHP: Constructing signal events – Manual
If I had to speculate: Also for python is pyevent, which works pretty well. And it leads to some nasty state bugs, because conditions that are obvious in sequential code “parse failed? It’s not a standard part of Unix, of course, but it seems reasonably portable. When we want to write data, for example, the usual pattern looks like:.
Fast portable non-blocking network programming with Libevent
RoboTeddy on Jan 11, This will close an underlying socket, free an underlying buffer event, etc. There are plenty of services that won’t ever need to handle more than a couple simultaneous connections, and that way you don’t need to bother with asynchronous IO.
This is hardly a new idea, in fact it’s very well-traveled ground. When this flag is set, the bufferevent defers all of its callbacks.
UNIX for Advanced & Expert Users
Decide that blcoking want to write some data to a connection; put that data in a buffer. That can be extremely bad for latency.
It makes “what happens next” a really hard problem. Where I work, there’s one single library for concurrency, and every program or toolkit uses it. If you need to handle lots of concurrent connections and don’t need to be working in C, check it out.