Speeding up require in ember

[SamSaffron]

@stefanpenner been looking at requireInternal in Ember.

Seems like we can get some perf here by preallocating the array http://jsperf.com/preallocating-array/23

var reified = [];
      var length = deps.length;

      for (var i=0; i<length; i++) {
        if (deps[i] === 'exports') {
          reified.push(exports);
        } else {
          reified.push(internalRequire(resolve(deps[i], name), name));
        }
      }

reified can be preallocated then you don't need to push

Thoughts?

[SamSaffron]

Also I wonder if we can somehow get rid of the recursion there, it will make it way easier for js engines to optimize

[rwjblue]

Preallocating sounds fine (and easy enough to do), but I'd like to see via benchmarks if it makes a practical difference here.

[stefanpenner]

@SamSaffron -> #11576

the best way to reduce cost here is to do less of it, currently ember does far to much upfront internal requiring. Which hits v8 pretty hard, we can invert this and make it more paygo. the above PR demonstrates a pretty substantial win, just needs someone with cycles to move the idea forward.

[stefanpenner]

@SamSaffron yes, reified should/could be pre-allocated.

[stefanpenner]

@SamSaffron if you have time, I would love to get a quick and dirty benchmark suite for loader.js -> https://github.com/ember-cli/loader.js maybe using https://github.com/stefanpenner/do-you-even-bench

[stefanpenner]

I patched embers heavily patched loader to do this, i was going to update loader.js proper but realized it already does this: https://github.com/ember-cli/loader.js/blob/master/loader.js#L72-L73

[krisselden]

So ember doesn't use the same loader?

[stefanpenner]

They begun life together. Embers loader has been hacked up, it would be nice to reconverge at some point

[gogogarrett]

Is there any information anywhere about the differences between the two and what context each are used for?

[rwjblue]

So ember doesn't use the same loader?

No.

They begun life together.

In the beginning, there was only Ember's loader. We had like 5 different versions inlined in various projects before ember-cli/loader.js was extracted and made the primary one.

Is there any information anywhere about the differences between the two

diff https://github.com/ember-cli/loader.js/blob/master/loader.js and https://github.com/emberjs/ember.js/blob/master/packages/loader/lib/main.js

[stefanpenner]

As we move to addonify ember, we will want the app and ember to sure a loader. (I believe) at which some form of unification must be done.