Novice, Practiced, Mastered
Have ideas to improve npm?Join in the discussion! »

fastparallel

2.4.0 • 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:

benchSetImmediate*1000000: 1378.514ms
benchAsyncParallel*1000000: 1740.304ms
benchAsyncEach*1000000: 1566.517ms
benchAsyncMap*1000000: 1687.518ms
benchNeoParallel*1000000: 1388.223ms
benchNeoEach*1000000: 1473.006ms
benchNeoMap*1000000: 1402.986ms
benchInsyncParallel*1000000: 1957.863ms
benchInsyncEach*1000000: 1383.822ms
benchInsyncMap*1000000: 1822.954ms
benchItemsParallel*1000000: 1690.118ms
benchParallelize*1000000: 1570.064ms
benchFastParallel*1000000: 1536.692ms
benchFastParallelNoResults*1000000: 1363.145ms
benchFastParallelEachResults*1000000: 1508.134ms
benchFastParallelEach*1000000: 1325.314ms

Obtained on node 12.18.2, on a dedicated server.

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

55,923

Version

2.4.0

License

ISC

Unpacked Size

22.8 kB

Total Files

9

Last publish

Collaborators

  • avatar