You don't want your CPU intensive code to execute async, you want it to execute in parallel. You need to get the processing work out of the thread that's serving HTTP requests. It's the only way to solve this problem. With NodeJS the answer is the cluster module, for spawning child processes to do the heavy lifting. (AFAIK Node doesn't have any concept of threads/shared memory; it's processes or nothing). You have two options for how you structure your application. You can get the 80/20 solution by spawning 8 HTTP servers and handling compute-intensive tasks synchronously on the child processes. Doing that is fairly simple. You could take an hour to read about it at that link. In fact, if you just rip off the example code at the top of that link you will get yourself 95% of the way there.

另一种构造方法是设置一个作业队列，并在队列上发送大型计算任务。请注意，对于作业队列，IPC有很多相关的开销，因此这只在任务明显大于开销时才有用。

令我惊讶的是，这些其他答案都没有提到集群。

背景: 异步代码是挂起的代码，直到在其他地方发生某些事情，此时代码将被唤醒并继续执行。一种非常常见的情况是，在其他地方必须发生一些缓慢的事情，那就是I/O。

如果异步代码是由处理器负责处理的，那么异步代码就没有用处。这正是“计算密集型”任务的情况。

现在，异步代码似乎是小众的，但实际上它非常普遍。它只是碰巧对计算密集型任务没有用处。

Waiting on I/O is a pattern that always happens in web servers, for example. Every client who connects to your sever gets a socket. Most of the time the sockets are empty. You don't want to do anything until a socket receives some data, at which point you want to handle the request. Under the hood an HTTP server like Node is using an eventing library (libev) to keep track of the thousands of open sockets. The OS notifies libev, and then libev notifies NodeJS when one of the sockets gets data, and then NodeJS puts an event on the event queue, and your http code kicks in at this point and handles the events one after the other. Events don't get put on the queue until the socket has some data, so events are never waiting on data - it's already there for them.

单线程基于事件的web服务器作为一种范式是有意义的，当瓶颈正在等待一堆空的套接字连接时，你不希望每个空闲连接都有一个完整的线程或进程，你也不希望轮询你的250k套接字来寻找下一个有数据的套接字。

有几种方法可以使用。

正如@Tim指出的那样，您可以创建一个位于主要服务逻辑之外或并行的异步任务。这取决于您的确切需求，但即使是cron也可以充当队列机制。

webworker可以为你的异步进程工作，但node.js目前不支持。有几个扩展提供了支持，例如:http://github.com/cramforce/node-worker

您仍然可以通过标准的“要求”机制重用模块和代码。您只需要确保向工作人员的初始分派传递处理结果所需的所有信息。

使用child_process是一种解决方案。但是与Go Go例程相比，生成的每个子进程可能会消耗大量内存

您还可以使用基于队列的解决方案，例如kue

您需要的是一个任务队列!将长时间运行的任务移出web服务器是一件好事。将每个任务保存在“单独的”js文件中可以促进模块化和代码重用。它迫使您考虑如何以一种更容易调试和长期维护的方式来组织您的程序。任务队列的另一个好处是工作线程可以用不同的语言编写。只需弹出一个任务，完成工作，然后返回响应。

就像这样https://github.com/resque/resque

这是一篇来自github的文章，关于他们为什么要建立它http://github.com/blog/542-introducing-resque

这是对web服务器定义的误解——它应该只用于与客户端“对话”。重载任务应该委托给独立的程序(当然也可以用JS编写)。 你可能会说它很脏，但我向你保证，一个web服务器进程卡在调整图像的大小是更糟糕的(即使是Apache，当它不阻止其他查询)。不过，您可以使用公共库来避免代码冗余。

编辑:我想出了一个类比;Web应用程序应该像一家餐厅。你有服务员(网络服务器)和厨师(工人)。服务员与顾客保持联系，做一些简单的工作，比如提供菜单或解释某道菜是否是素食的。另一方面，他们把更艰巨的任务委托给厨房。因为服务员只做简单的事情，他们反应迅速，厨师可以集中精力工作。

Node.js将是一个单一但非常有才华的侍者，一次可以处理许多请求，而Apache将是一群愚蠢的侍者，每个人只处理一个请求。如果这个Node.js服务员开始做饭，那将是一场直接的灾难。尽管如此，烹饪也可能耗尽大量阿帕奇服务员的精力，更不用说厨房里的混乱和反应能力的逐渐下降。

You don't want your CPU intensive code to execute async, you want it to execute in parallel. You need to get the processing work out of the thread that's serving HTTP requests. It's the only way to solve this problem. With NodeJS the answer is the cluster module, for spawning child processes to do the heavy lifting. (AFAIK Node doesn't have any concept of threads/shared memory; it's processes or nothing). You have two options for how you structure your application. You can get the 80/20 solution by spawning 8 HTTP servers and handling compute-intensive tasks synchronously on the child processes. Doing that is fairly simple. You could take an hour to read about it at that link. In fact, if you just rip off the example code at the top of that link you will get yourself 95% of the way there.

另一种构造方法是设置一个作业队列，并在队列上发送大型计算任务。请注意，对于作业队列，IPC有很多相关的开销，因此这只在任务明显大于开销时才有用。

令我惊讶的是，这些其他答案都没有提到集群。

背景: 异步代码是挂起的代码，直到在其他地方发生某些事情，此时代码将被唤醒并继续执行。一种非常常见的情况是，在其他地方必须发生一些缓慢的事情，那就是I/O。

如果异步代码是由处理器负责处理的，那么异步代码就没有用处。这正是“计算密集型”任务的情况。

现在，异步代码似乎是小众的，但实际上它非常普遍。它只是碰巧对计算密集型任务没有用处。

Waiting on I/O is a pattern that always happens in web servers, for example. Every client who connects to your sever gets a socket. Most of the time the sockets are empty. You don't want to do anything until a socket receives some data, at which point you want to handle the request. Under the hood an HTTP server like Node is using an eventing library (libev) to keep track of the thousands of open sockets. The OS notifies libev, and then libev notifies NodeJS when one of the sockets gets data, and then NodeJS puts an event on the event queue, and your http code kicks in at this point and handles the events one after the other. Events don't get put on the queue until the socket has some data, so events are never waiting on data - it's already there for them.

单线程基于事件的web服务器作为一种范式是有意义的，当瓶颈正在等待一堆空的套接字连接时，你不希望每个空闲连接都有一个完整的线程或进程，你也不希望轮询你的250k套接字来寻找下一个有数据的套接字。