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 [19], 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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JoachimSchipper on Jan 11, 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 liebvent read or written enough data.

The EventBufferEvent class

The short answer may very well be no, since it somewhat depends on the programming language one chooses to use. Fork-per-connection sequential is simple and pretty fast, but it does have its limits it works fine for a simple webapp, but writing a high-performance IRC server that way will be rather painful.

Lots of huge sites rely on memcache, for example, which would suck if it didn’t use event-based IO. 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.

PHP: Constructing signal events – Manual

Equals to NULLif there is no file descriptor socket associated with the buffer event. It was used heavily in the 90’s when threaded multiplexing was still new and threads were expensiveand it works well enough. It splits sequential algorithms up witn multiple callbacks with manually managed shared state.


Libevent is rock solid — it handles the event loop for memcache, among other things. It isn’t snake oil – it works and works well in the right situations.

Hacker News new comments show ask jobs submit. It uses greenlets to make code written sychronously run asynchronously behind the scenes.

Again, event stuff has been here forever, and clearly is appropriate for some tasks. If you have any other links, please share. Multiple requests can be running in parallel without fully blocking each other. When we want to write data, for example, the usual pattern looks like:. Underlying output buffer object EventBuffer. It feels sort of fzst writing in continuation-passing-style.

Fast portable non-blocking network programming with Libevent | Hacker News

This is hardly a new idea, in fact it’s very well-traveled ground. There are plenty of services that won’t ever need to handle more than a couple simultaneous connections, porhable that way you don’t need to bother with asynchronous IO. But most apps don’t fall into those categories, and I’m not getting any of that vibe from this. I have used it to much success — some people don’t like the minimalist style.

We do a lot of network lubevent, so it would be unthinkable for any performance intensive application to do blocking calls exclusively. It makes “what happens next” a really hard problem.

When this flag is set, the bufferevent defers all of its callbacks.

Fast portable non-blocking network programming with Libevent

An error occurred during a faast operation. I submitted the link. I’ve been networj about multiplexing asynchronous IO because I’m writing a distributed filesystem of sorts. It’s not a standard part of Unix, of course, but it seems reasonably portable.

That no common means have been invented for that is what I’m sad about. Where I work, there’s one single library for concurrency, and every program or toolkit uses it. There’s a Python project called gevent http: Within a single thread they do serialize, but only by the length of your callbacks. That means you’ll often be stuck with limited capabilties, unless you write your own libraries or hack up existing ones. If I had to speculate: For more information on what the error was, call EventUtil:: It seems like a good fit for both the indexing hubs and the storage nodes, and it pairs well with Lua’s coroutines.


Sure, but libraries underneath you have to cooperate for you to use it to the fullest potential. And the truth isn’t like that at all, and in fact these are truths that we’ve all known for libeveny now JoachimSchipper on Jan 11, Fork-per-connection sequential is simple and pretty fast, but it does have its limits it works fine for a simple webapp, but writing a high-performance IRC server that way will be progrramming painful.

Underlying input buffer object EventBuffer. RoboTeddy on Jan 11, Anyway, I’m netsork curious Thanks. Event programming is useful in that it effectively performs cooperative multitasking without the overhead of thread stack space. Normally represents a bound socket. It’s too bad that no standard method for a asynchronous events has been developed for Unix in general. Portble file descriptor associated with the buffer event. If you run a single thread without the event based approacheach request must wait for preceding requests to finish entirely before running.

I know what you mean about an event loop complicating error handling from callbacks, though. RoboTeddy on Jan 11, Libevent libegent rock solid — it handles the event loop for memcache, among other things. So if you’re writing the client handler for a database, or something like memcached, you need this technique whether you need an abstraction library is another argument Also for python is pyevent, which works pretty well.