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POConfusion about node.js internal asynchronous I/O mechanism
 

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  1. POConfusion about node.js internal asynchronous I/O mechanism
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    <ol> <li>I have learned that node.js use libeio internally to perform async <strong>file</strong> I/O, with thread pool, on *nix platform, am I right? </li> <li>What about async <strong>network</strong> I/O? Is it done by libev? Is there also a thread pool? </li> <li>If there is thread pool inside, how could it be more efficient than traditional one-thread-per-request model? And is it one thread per I/O request?</li> <li>And what's the mechanism on windows? I know it's done by IOCP, and there's a kernel level thread pool, right?</li> <li>Why linux doesn't have a native completely AIO mechanism like windows IOCP yet? Will it have in future?</li> </ol> <p>Update according to changchang's answer: </p> <ol> <li>I took a quick view at the <a href="https://github.com/joyent/libuv/blob/master/src/unix/threadpool.c" rel="noreferrer">source code</a> @changchang have given, found that the default thread pool size can be reset by <strong>UV_THREADPOOL_SIZE</strong>, I'm wondering in which case this will be used? </li> <li>I also found getaddrinfo use this thread pool, is there any more except fs? And if all sync jobs will be done in this thread pool, is the default size '4' enough? </li> <li>As my understanding now, there will be 6 basic threads in node.js process: 1 V8 thread(event loop, where user javascript codes runs), 1 libuv event loop, and 4 in thread pool, am I right? </li> <li><p>And how can I see these threads in my shell(Ubuntu)? I use <strong>ps -eLf | grep node | grep -v grep</strong> only saw two:</p> <p>root 16148 7492 16148 0 2 20:43 pts/26 00:00:00 ./bin/node /home/aaron/workspace/test.js<br> root 16148 7492 16149 0 2 20:43 pts/26 00:00:00 ./bin/node /home/aaron/workspace/test.js</p></li> </ol>
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    1. COSee here http://stackoverflow.com/questions/10680601/nodejs-event-loop
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      1. POConfusion about node.js internal asynchronous I/O mechanism
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    2. COnode.js actually uses [libuv](https://github.com/joyent/libuv/) to abstract asynchronous IO for all supported platforms
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      1. POConfusion about node.js internal asynchronous I/O mechanism
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    3. CO@user568109 I have read that, but cant't get straight answer from it, actually, unclear expression confuse me more. It mentioned that libeio 'perform input output asynchronously' including sockets, I doubt that. I learned this from somewhere that: because can't use epoll on regular files, so here comes libeio to perform aio with threads.
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