[webkit-dev] Feature announcement: WebCL

Oliver Hunt oliver at apple.com
Tue Apr 30 17:36:18 PDT 2013

Before i saw any patches landed i would expect the specification to state exactly what kernel features are allowed and required.

Additionally the specification language of the security section is fairly weak - 4.2 doesn't say how CORS will be used to achieve security.  Presumably WebCL just wants the WebGL security resource semantics, but the language needs to be explicit.

How is 4.3 enforced?

The only way to reliably enforce 4.4 is to either restrict the valid kernel constructs (see my first point - you aren't defining the kernel semantics sufficiently well), or to avoid ever pushing the kernels onto a gpu.  On the plus side not pushing the kernel to the GPU means executing on the CPU, and so having the benefit of sane interruption and memory access behavior, which neatly solves 4.6.

I'd rather not support the half-float format anywhere, as that simply means at some point in the communication paths we end up having to do a software double or single to half conversion, and back again later, all in order to support older GPUs that don't support single, assuming we even let the kernel get anywhere near the gpu.

In general I don't like the design of the API, I believe it over-exposes system information and doesn't sufficiently define edge case behavior.


On Apr 30, 2013, at 5:10 PM, Antonio Gomes <tonikitoo at webkit.org> wrote:

> Hello.
> As discussed before, Khronos has been working on a specification for WebCL, a JavaScript API that exposes GPUs and multi-core processors for intensive compute tasks. The latest version of the working draft is available here: [1].
> Over the past weeks, some discussion involving WebCL took place in this mailing list ([2]), when some concerns were raised, and to which I later on tried to address in [3].
> At this time, I would like to contribute our WebCL prototype implementation [4] to WebKit.org.
> Feature would be defined behind a ENABLE(WEBCL) feature flag, and work will be tracked onhttps://bugs.webkit.org/show_bug.cgi?id=115457.
> Let me know if you have any comments or concerns.
> Cheers,
> [1] https://cvs.khronos.org/svn/repos/registry/trunk/public/webcl/spec/latest/index.html 
> [2] https://lists.webkit.org/pipermail/webkit-dev/2013-April/024546.html
> [3] https://lists.webkit.org/pipermail/webkit-dev/2013-April/024747.html
> [4] https://github.com/SRA-SiliconValley/webkit-webcl 
> -- 
> --Antonio Gomes
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> https://lists.webkit.org/mailman/listinfo/webkit-dev

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