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fastparallel

2.3.0 • Public • Published

fastparallel Build Status

Zero-overhead parallel function call for node.js. Also supports each and map!

Benchmark for doing 3 calls setImmediate 1 million times:

  • non-reusable setImmediate: 1781ms
  • async.parallel: 3484ms
  • async.each: 2621ms
  • async.map: 3054ms
  • neoAsync.parallel: 2162ms
  • neoAsync.each: 2156ms
  • neoAsync.map: 2080ms
  • insync.parallel: 10252ms
  • insync.each: 2397ms
  • insync.map: 9700ms
  • items.parallel: 3725ms
  • parallelize: 2928ms
  • fastparallel with results: 2139ms
  • fastparallel without results: 1957ms
  • fastparallel map: 2102ms
  • fastparallel each: 1941ms

These benchmarks where taken via bench.js on node v4.2.2, on a MacBook Pro Retina Mid 2014 (i7, 16GB of RAM).

If you need zero-overhead series function call, check out fastseries. If you need a fast work queue check out fastq. If you need to run fast waterfall calls, use fastfall.

js-standard-style

The major difference between version 1.x.x and 2.x.x is the order of results, this is now ready to replace async in every case.

Example for parallel call

var parallel = require('fastparallel')({
  // this is a function that will be called
  // when a parallel completes
  released: completed,
 
  // if you want the results, then here you are
  results: true
})
 
parallel(
  {}, // what will be this in the functions
  [something, something, something], // functions to call
  42, // the first argument of the functions
  done // the function to be called when the parallel ends
)
 
function something (arg, cb) {
  setImmediate(cb, null, 'myresult')
}
 
function done (err, results) {
  console.log('parallel completed, results:', results)
}
 
function completed () {
  console.log('parallel completed!')
}

Example for each and map calls

var parallel = require('fastparallel')({
  // this is a function that will be called
  // when a parallel completes
  released: completed,
 
  // if you want the results, then here you are
  // passing false disables map
  results: true
})
 
parallel(
  {}, // what will be this in the functions
  something, // functions to call
  [1, 2, 3], // the first argument of the functions
  done // the function to be called when the parallel ends
)
 
function something (arg, cb) {
  setImmediate(cb, null, 'myresult')
}
 
function done (err, results) {
  console.log('parallel completed, results:', results)
}
 
function completed () {
  console.log('parallel completed!')
}
 

Caveats

The done function will be called only once, even if more than one error happen.

This library works by caching the latest used function, so that running a new parallel does not cause any memory allocations.

Why it is so fast?

  1. This library is caching functions a lot.

  2. V8 optimizations: thanks to caching, the functions can be optimized by V8 (if they are optimizable, and I took great care of making them so).

  3. Don't use arrays if you just need a queue. A linked list implemented via processes is much faster if you don't need to access elements in between.

  4. Accept passing a this for the functions. Thanks to this hack, you can extract your functions, and place them in a outer level where they are not created at every execution.

License

ISC

install

npm i fastparallel

Downloadsweekly downloads

8,516

version

2.3.0

license

ISC

homepage

github.com

repository

Gitgithub

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