Re: [boost] [compute] GPGPU Library - Request For Feedback

Subject: Re: [boost] [compute] GPGPU Library - Request For Feedback
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2013-03-02 21:15:28

> A while back I posted a message asking for interest in a GPGPU computing
> library and the response seemed positive. I've been slowly working on it
> for the last few months and it has finally reached a usable state. I've
> made an initial release on GitHub (details below) and would like to get
> feedback from the community.
> 
> The Boost Compute library provides a partial implementation of the C++
> standard library for GPUs and multi-core CPUs. It includes common
> containers (vector<T>, flat_set<T>) and standard algorithms (transform,
> sort, accumulate). It also features a number of extensions including
> parallel-computing focused algorithms (exclusive_scan, scatter, reduce)
> along with a number of fancy iterators (transform_iterator,
> permutation_iterator). The library is built around the OpenCL framework
> which allows it to be portable across many types of devices (GPUs, CPUs,
> and accelerator cards) from many different vendors (NVIDIA, Intel, AMD).
> 
> The source code and documentation are available from the links below.
> 
> Code: https://github.com/kylelutz/compute
> Documentation: http://kylelutz.github.com/compute
> Bug Tracker: https://github.com/kylelutz/compute/issues
> 
> I've tested the library with GCC 4.7 and Clang 3.3 on both NVIDIA GPUs and
> Intel CPUs. However, I would not yet consider the library production-
> ready.
> Most of my time has been devoted to reaching a solid and well-tested API
> rather than on performance. Over time this will improve.
> 
> Feel free to send any questions, comments or feedback.

Looks interesting. One question: what support does the library provide to
orchestrate parallelism, i.e. doing useful work while the GPGPU is executing
a kernel? Do you have something like:

int main()
{
    // create data array on host
    int host_data[] = { 1, 3, 5, 7, 9 };

    // create vector on device
    boost::compute::vector<int> device_vector(5);

    // copy from host to device
    future<void> f = boost::compute::copy_async(host_data,
                         host_data + 5,
                         device_vector.begin());

    // do other stuff

    f.get();   // wait for transfer to be done

    return 0;
}

?

All libraries I have seen so far assume that the CPU has to idle while
waiting for the GPU, is yours different?

Regards Hartmut
---------------
http://boost-spirit.com
http://stellar.cct.lsu.edu