Re: [Public WebCL] HTML5 and GPU acceleration

[Evgeny Demidov <demidov@ipm.sci-nnov.ru>]

Comments to the "The Mandelbrot set 1024x769 animation"
http://www.ibiblio.org/e-notes/webcl/mandelbrot_anim1.html

Bottlenecks
1. Kernel calculations take 30-45 msec (black regions are calculated 
slower) i.e. 22-30 fps.
2. I don't see delay by the data transfer from GPU and into TypedArray 
conversion (i.e. < 10msec).
3. ctx_c.putImageData(imgd, 0, 0) takes 10-20 msec.
4. Surprisingly pix array calculation takes 60 msec.
So 45+60 msec make about 8-9 fps! I'll transfer pix calculations into 
GPU but it increases GPU output 4 times.

OpenCL feature
Compiler asks for the cl_khr_byte_addressable_store extension (not 
supported by HD 4870) if I try to use short (2 bytes) data in the kernel 
output array. So I can't use unsigned char for pix too.
You need many OpenCL extensions and very recent GPU to write accurate 
scripts.

Evgeny
> hi,
>
> It's not very important (WebGL one year ago was not very fast too :) 
> but "just for fun"
> Where is bottleneck in the "M-set animation. Deep zoom" 1024x768 
> movies at
> http://www.ibiblio.org/e-notes/webcl/webcl.htm
> I'd like to make full screen movies :)
>
> Double precision floats work under Radeon 4870 and Fermy with
> #ifdef cl_khr_fp64
> #pragma OPENCL EXTENSION cl_khr_fp64 : enable
> #else
> #pragma OPENCL EXTENSION cl_amd_fp64 : enable
> #endif
>
> but I have to add checking of the 
> "plat.getPlatformInfo(WebCL.CL_PLATFORM_EXTENSIONS)" string for these 
> extensions.
>
> Do smartphones support OpenCL? double floats? :)
>
> Evgeny
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