[webkit-dev] Is there a plan for supporting multi-process and WebCL in webkit

[Oliver Hunt]

The parallel arrays apis aren't a magic "make my code parallel" wand.

They don't make general code parallel, they simply provide a bunch of functions like map, etc where if you restrict your list of language features to a specific subset, they'll vectorise it.

For instance

ParallelArray([1,2,3]).map(function(a,v) { return v * 2; })

would be vectorised

ParallelArray([1,2,3]).map(function(a,v) { return v.x * 2; })

wouldn't be.

This isn't "solve autovectorisation", this is "we've been given a specific operation to perform on each element of an array, parallelise it if possible", and what's possible is arbitrarily limited, and require a distinct type that isn't an array.

--Oliver

On Apr 10, 2013, at 12:37 PM, Dirk Pranke <dpranke at chromium.org> wrote:

> 
> 
> 
> On Wed, Apr 10, 2013 at 7:37 AM, Filip Pizlo <fpizlo at apple.com> wrote:
> 
> 
> On Apr 10, 2013, at 2:29 AM, "Pozdnyakov, Mikhail" <mikhail.pozdnyakov at intel.com> wrote:
> 
> >
> >
> >> Why not infer ParallelArrays automatically?
> > Sorry, did not get it. Could you please elaborate?
> 
> Normal JS arrays. You use them with pure computation. Profiler notices this. And then the same things that you have in the ParallelArrays proposal now work except you don't need a new type.
> 
> 
> Compiler writers have been chasing this problem for 50 years, with (AFAIK) very limited success for languages that don't give you compile-time annotations to help you along. I'm not aware of any work on JIT compilers doing this. Why do you think we could do better? (Honest question, I'm not trying to be snarky, nor am I an expert).
>  
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> https://lists.webkit.org/mailman/listinfo/webkit-dev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-dev/attachments/20130410/c638ce30/attachment.html>