Hey,

2014/1/25 Karl Rupp <r...@iue.tuwien.ac.at>

> Hey hey hey,
>
>
> >     Convergence depends on what is inside generate_execute() ;-) How is
>
>>     the problem with alpha and beta residing on the GPU addressed? How
>>     will the batch-compilation look like? The important point is that
>>     for the default axpy kernels we really don't want to go through the
>>     jit-compiler for each of them individually.
>>
>>
>> ;)
>> in this case, generate_execute() will just trigger the compilation - on
>> the first call only - of the kernel
>> x = cpu_alpha*y + cpu_beta*z;
>>
>> __kernel void kernel(unsigned int N, float4* x, float4* y, float4* z,
>> float alpha, float beta)
>> {
>>    for(i = get_global_id(0) ; i < N ; i+=get_global_size(0))
>>      x[i] = alpha*y[i] + beta*z[i];
>> }
>>
>
> I'm afraid this is not suitable then. A simple conjugate gradient solver
> would then go through ~10 OpenCL compilations, making it awfully slow at
> the first run... With AMD and Intel SDKs, which to my knowledge still do
> not buffer kernels, this would mean that each time a process is started,
> this large overhead will be visible.
>
>
I don't understand why this would go through more than one compilation...
This kernel is compiled only once, the value of flip_sign and reciprocal
only changes the dynamic value of the argument, not the source code.

This would eventually result in:

if(alpha_reciprocal)
   kernel(N,x,y,z,1/alpha,beta)

Am I missing something?

Best regards,
Philippe

Best regards,
> Karli
>
>
>
------------------------------------------------------------------------------
CenturyLink Cloud: The Leader in Enterprise Cloud Services.
Learn Why More Businesses Are Choosing CenturyLink Cloud For
Critical Workloads, Development Environments & Everything In Between.
Get a Quote or Start a Free Trial Today. 
http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk
_______________________________________________
ViennaCL-devel mailing list
ViennaCL-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/viennacl-devel

Reply via email to