[whatwg] Script preloading: Browser Pre-compiled Scripts Cache?
bzbarsky at MIT.EDU
Mon Jul 15 06:30:17 PDT 2013
On 7/15/13 3:42 AM, Bruno Racineux wrote:
> Wouldn't browsers be able to store "pre-parsed/compiled' scripts in a
> separate "byte code" cache,
You mean like https://bugzilla.mozilla.org/show_bug.cgi?id=679942 ?
There's some discussion in there about whether this is a worthwhile
optimization with modern JS engines, which feature lazy compilation and
even lazy parsing to a large extent.... Measurement is needed of the
various pieces discussed in
In either case, note that there is already caching of this sort to some
extent in SpiderMonkey; see
https://bugzilla.mozilla.org/show_bug.cgi?id=883154 which is fixed.
Note that in the context of that bug a "script" is what you probably
think of as a "function body": that's the fundamental unit of
compilation in SpiderMonkey now that we do lazy compilation.
> i.e. Why do we have to keep re-parsing and re-evaluating the very same
> scripts, especially CDN libraries and social apis largely shared among
> websites, over and over?
The re-evaluating is because evaluation has little things like
> the whole parse/evaluation time, could be cut 'partially', yet very significantly
Some hard data would be useful here, as I said above.
More information about the whatwg