Example of creating a pool of Web Workers

WorkerPool.js

function WorkerPool(url) {
    this.url = url;
    this.pool = [];
}
WorkerPool.prototype.getWorker = function() {
    var w;
    if (this.pool.length > 0) {
        w = this.pool.pop();
    } else {
        w = new Worker(this.url);
    }
    return w;
}
WorkerPool.prototype.releaseWorker = function(w) {
    this.pool.push(w);
}

// Create a new pool
var my_pool = new WorkerPool("fib.js");

// Get a worker from the pool and use it
var worker = my_pool.getWorker();
worker.onmessage = function(e) {
    // Do stuff, then release worker if no longer working.
    my_pool.releaseWorker(worker);
}
worker.postMessage("start");

Here is a naive pattern for implementing pools of Web Workers, to enable re-use when used heavily. I think this is possibly beneficial for a few reasons.

• There's a small hit when creating a Worker, which there isn't when popping one from an existing pool.
• In Webkit (and maybe others?), Worker files are re-requested from the server when creating a new Worker. This could be mitigated to a large degree by properly caching, but still.
• Chrome (I think) limits the number of Workers allowed to 16, which means you'd have to re-use or queue tasks in someway - but perhaps this can be better handled within one Worker process?

This would also need to set a limit for the number of Workers and allow for queuing tasks until threads are available. Are there existing patterns/code out there for doing this well? Is this even valuable? Or am I doing it wrong?

hey Andy!
did you find any library/solution which meets your requirements?
I also found your answer on stackoverflow and it looks like I'm looking for something similiar.

http://slowfrog.blogspot.de/2011/05/taking-advantage-of-multiple-cores-with_25.html
this article seems to be very helpful