Re: [boost] SYCL (RE: [compute] review)

Subject: Re: [boost] SYCL (RE: [compute] review)
From: Sebastian Schaetz (seb.schaetz_at_[hidden])
Date: 2014-12-28 20:11:16

Gruenke,Matt <mgruenke <at> Tycoint.com> writes:

> 
> 
> -----Original Message-----
> From: Boost [mailto:boost-bounces <at> lists.boost.org] On Behalf Of Kyle Lutz
> Sent: Sunday, December 28, 2014 14:42
> To: boost <at> lists.boost.org List
> Subject: Re: [boost] [compute] review
> 
> > On Sun, Dec 28, 2014 at 1:54 AM, Gruenke,Matt wrote:
> 
> > Others libraries/frameworks (such as SYCL, Bolt, C++AMP, OpenACC, etc.)
> > are all dependent on either a special compiler or special compiler
extensions.
> 
> According to Khronos, that's incorrect.
> 
>     The provisional specification includes the following features:
> 
>     * Specifications for creating C++ template libraries and compilers
>       using the C++11 standard
> 
>     * Easy to use, production grade API - built on-top of OpenCL and SPIR(tm)
> 
>     * Compatible with standard CPU C++ compilers across multiple platforms,
>       ^^^^^^^^^^ ^^^^ ^^^^^^^^ ^^^ ^^^ ^^^^^^^^^
>       as well as enabling new SYCL device compilers to target OpenCL devices
> 
>     * Asynchronous, low-level access to OpenCL features for high performance
>       and low-latency - while retaining ease of use
> 
> Source: https://www.khronos.org/opencl/sycl

Slides 14 and 15 of this slidedeck [0] show SYCL device compilers. SYCL code
compiles using a standard C++11 compiler. To compile SYCL code however you
need "either a special compiler or special compiler extensions". Codeplay
calls this "Shared Source Programming Model", you can learn more about it
from slides 22 onwards in this slide deck [1]. It is the same thing CUDA is
doing since its initial release.

But that is not unexpected at all. I don't think there is a technique to
generate kernel code from 

command_group(myQueue, [&]()
{
  // Data accessors
  // [...]
  // Kernel
  parallel_for(count, kernel_functor([ = ](id<> item) {
    int i = item.get_global(0);
    r[i] = a[i] + b[i] + c[i];
  }));
});

within standard C++11. You need a second compiler or an extension.

Boost.Compute can do most things SYCL can do - except you don't need
anything but a regular C++ compiler and the OpenCL library.

[0] http://tinyurl.com/q7f5nm4
[1] http://tinyurl.com/nffyyon