Switching to async/await from Task.jsm/yield

Kris Maglione kmaglione at mozilla.com
Fri Mar 17 23:41:24 UTC 2017

On Fri, Mar 17, 2017 at 07:30:46PM -0400, Ehsan Akhgari wrote:
>Have we measured the performance of our async/await implementation?  I
>think we should definitely do some extensive testing of the performance
>of any new ES primitives before deciding to switch to using them in the
>front-end code en masse.  Of course, if the performance result aren't
>good, that doesn't mean we shouldn't use them in the front-end code, it
>means we need to make the performance better.  :-)  But we need to be
>able to make the trade-off cautiously.

Yes. There was performance testing for the self-hosted version 
(which was basically the same as the Promise.jsm implementation) 
before it was converted to C++, and after:


In short, it's better, but not hugely.

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